STI STM32091C-EVAL User manual

June 2016 DocID026902 Rev 3 1/58
1
UM1817
User manual
Evaluation board with STM32F091VC MCU
Introduction
The STM32091C-EVAL evaluation board is designed as a complete demonstration and
development platform for STMicroelectronics ARM®Cortex®-M0 core-based
STM32F091VCT6 microcontroller, with two I2Cs, two SPIs, eight USARTs, one CAN, 12-bit
ADC, 12-bit DAC, two GP comparators, internal SRAM and 256-Kbyte Flash memory,
Touch sensing, CEC and SWD debugging support.
The full range of hardware features on the board helps the user to evaluate all the
peripherals (8x USARTs, RS-232, RS-485, Audio DAC, microphone ADC, Touch sensing
buttons, TFT LCD, CAN, IrDA, IR LED, IR receiver, LDR, microSD card, CEC on two HDMI
connectors, smartcard slot, RF-EEPROM and temperature sensor) and to develop
applications. Extension headers make it possible to easily connect a daughterboard or
wrapping board for a specific application. An ST-LINK/V2-1 is integrated on the board as an
embedded in-circuit debugger and programmer for the STM32.
Figure 1. STM32091C-EVAL evaluation board
1. Picture not contractual.
www.st.com

Contents UM1817
2/58 DocID026902 Rev 3
Contents
1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.1 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.2 Demonstration software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3 Order code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.4 Delivery recommandations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Hardware layout and configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Embedded ST-LINK/V2-1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
2.1.1 Drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.1.2 ST-LINK/V2-1 firmware upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.2 Board power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3 STM32 power-mode configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.4 Clock source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
2.5 Reset source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.6 Boot option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.7 Audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.8 RS-232, RS-485 and IrDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.9 Touch sensing buttons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
2.10 microSD card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.11 Analog input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2.12 LDR (Light Dependent Resistor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.13 Temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.14 Smartcard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.15 CAN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2.16 RF-EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.17 HDMI CEC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
2.18 IR LED and IR receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.19 8x USARTs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
2.20 Display and input devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3 Connectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.1 8x USARTs connector CN1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

DocID026902 Rev 3 3/58
UM1817 Contents
3
3.2 RF-EEPROM connector CN2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
3.3 HDMI sink connector CN3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.4 HDMI source connector CN4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.5 CAN D-type 9-pin male connector CN5 . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.6 Daughterboard extension connectors CN6 and CN7 . . . . . . . . . . . . . . . . 29
3.7 microSD connector CN8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
3.8 RS-232 and RS-485 connector CN9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3.9 High density SWD connector CN10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
3.10 Standard SWD connector CN11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.11 ST-LINK/V2-1 USB Type-B connector CN12 . . . . . . . . . . . . . . . . . . . . . . 36
3.12 Audio jack CN13 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.13 FT LCD connector CN14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.14 ST-LINK/V2-1 programming connector CN15 . . . . . . . . . . . . . . . . . . . . . 36
3.15 Power connector CN16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.16 Analog input-output connector CN18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
3.17 Smartcard connector CN19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Appendix A STM32091C-EVAL IO assignment . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Appendix B Schematics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

List of tables UM1817
4/58 DocID026902 Rev 3
List of tables
Table 1. Mechanical dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Table 2. Power source related jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Table 3. Power mode related jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Table 4. Low-voltage limitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 5. 32 KHz crystal X1 related solder bridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 6. 8MHz crystal X2 related solder bridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Table 7. Boot related switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Table 8. Boot0 related jumpers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 9. Audio related jumpers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Table 10. RS-232 and IrDA related jumpers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Table 11. RS-485 related solder bridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Table 12. Touch sensing buttons related solder bridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Table 13. Temperature sensor or related solder bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Table 14. Connection between ST8024L and STM32F091VCT6 . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Table 15. CAN related jumpers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Table 16. LCD modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Table 17. 8x USARTs connector CN1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Table 18. RF-EEPROM connector CN2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 19. HDMI sink connector CN3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Table 20. HDMI source connector CN4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Table 21. CAN D-type 9-pin male connector CN5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 22. Daughterboard extension connector CN6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Table 23. Daughterboard extension connector CN7 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Table 24. microSD connector CN8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 25. RS-232 and RS-485 connector CN9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Table 26. High density SWD connector CN10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Table 27. Standard SWD debugging connector CN11 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Table 28. USB Type-B connector CN12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Table 29. Analog input-output connector CN18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Table 30. Smartcard connector CN19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Table 31. I/O assignment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Table 32. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

DocID026902 Rev 3 5/58
UM1817 List of figures
5
List of figures
Figure 1. STM32091C-EVAL evaluation board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Figure 2. Hardware block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 3. STM32091C-EVAL board layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 4. Mechanical dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Figure 5. USB Composite Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Figure 6. Structure of the power source. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Figure 7. GP comparator 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Figure 8. USART data flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Figure 9. 8x USARTs connector CN1 (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 10. RF-EEPROM daughterboard connector CN2 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . 26
Figure 11. HDMI sink connector CN3 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Figure 12. HDMI source connector CN4 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 13. CAN D-type 9-pin male connector CN5 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Figure 14. microSD connector CN8 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Figure 15. RS-232 and RS-485 connector CN9 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Figure 16. High density SWD debugging connector CN10 (top view) . . . . . . . . . . . . . . . . . . . . . . . . . 34
Figure 17. Standard SWD debugging connector CN11 (top view) . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Figure 18. USB Type-B connector CN12 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Figure 19. Power supply connector CN16 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Figure 20. Analog input-output connector CN18 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Figure 21. Smartcard connector CN19 (front view) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Figure 22. STM32091C-EVAL top view . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Figure 23. STM32091C-EVAL MCU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Figure 24. STM32091C-EVAL Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Figure 25. STM32091C-EVAL Audio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Figure 26. STM32091C-EVAL HDMI_CEC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Figure 27. STM32091C-EVAL LCD and microSD card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Figure 28. STM32091C-EVAL peripherals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Figure 29. STM32091C-EVAL RS-232, RS-485 and IrDA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Figure 30. STM32091C-EVAL temperature sensor and RF-EEPROM . . . . . . . . . . . . . . . . . . . . . . . . 50
Figure 31. STM32091C-EVAL CAN, smartcard and IR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Figure 32. STM32091C-EVAL SWD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Figure 33. STM32091C-EVAL touch sensing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Figure 34. STM32091C-EVAL ST-LINK/V2-1 (SWD only). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Figure 35. STM32091C-EVAL 8x_USART . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Figure 36. TFT LCD daughterboard MB895 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Overview UM1817
6/58 DocID026902 Rev 3
1 Overview
1.1 Features
•STM32F091VCT6 microncontroller with 256-Kbyte Flash memory and 32-Kbyte RAM
•Three 5 V power supply options: power jack, ST-LINK/V2-1 USB connector or
daughterboard
•Stereo audio jack which supports headset with microphone connected to DAC and
ADC of the STM32F091VCT6
•2-Gbyte (or more) SPI interface microSD card
•I2C compatible serial interface temperature sensor
•RF-EEPROM
•RS-232 and RS-485 communication
•IrDA transceiver
•IR LED and IR receiver
•SWD debug support, ST-LINK/V2-1 embedded
•240x320 TFT color LCD connected to SPI interface of STM32F091VCT6
•Joystick with 4-direction control and selector
•Reset, Tamper and user-buttons
•4-color user LEDs and two LEDs as STM32 low-power alarm
•Extension connector for daughterboard or wrapping board
•STM32 voltage choice fixed 3.3 V or adjustable from 1.65 V to 3.6 V
•Touch sensing buttons
•RTC with backup battery
•CAN2.0A/B compliant connection
•Light dependent resistor (LDR)
•Potentiometer
•Two HDMI connectors with DDC and CEC
•Smartcard slot
•8x USARTs chain connector
1.2 Demonstration software
Demonstration software is preloaded in the STM32F091VCT6 Flash memory for easy
demonstration of the device peripherals in stand-alone mode. For more information and to
download the latest version available, refer to the STM32091C-EVAL demonstration
software available on the www.st.com website.
1.3 Order code
To order the evaluation board for the STM32F091VCT6 MCU, use the order code
STM32091C-EVAL.

DocID026902 Rev 3 7/58
UM1817 Overview
57
1.4 Delivery recommandations
Before using the board for the first time, the user should check that it has not been visibly
damaged during the shipment, and that no components are unplugged or missing.
When the board is extracted from its plastic bag, check that no component remains in the
bag.
The main components to verify are:
1. The 8 MHz crystal (X2) which may have been removed from its socket by a shock.
2. The microSD card which may have been ejected from the CN8 connector (right side of
the board).
3. The dual-interface EEPROM board (ANT7-M24LR-A) which may have been unplugged
from the CN2 connector (top left corner of the board).
For all information concerning the version of the MCU used on the board, its specification
and possible related limitations, visit the ST web site www.st.com to download relevant
datasheet and errata sheet.

Hardware layout and configuration UM1817
8/58 DocID026902 Rev 3
2 Hardware layout and configuration
The STM32091C-EVAL evaluation board is designed around the STM32F091VCT6 (100-
pin LQFP package). The hardware block diagram Figure 2 illustrates the connection
between the STM32F091VCT6 and the peripherals (8x USARTs, RS-232, RS-485, Audio
DAC, microphone ADC, Touch sensing buttons, TFT LCD, CAN, IrDA, IR LED, IR receiver,
LDR, microSD card, CEC on two HDMI connectors, smartcard slot, RF-EEPROM and
Temperature sensor) and Figure 3 helps the user to locate these features on the actual
evaluation board. The Figure 4 and the Table 1 show the board mechanical dimensions.
Figure 2. Hardware block diagram
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UM1817 Hardware layout and configuration
57
Figure 3. STM32091C-EVAL board layout
CN2
RFEEPROM
daughterboard
connector
CN3
HDMI
Sink
CN12
ST-LINK/V2-1
USB
CN11
SWD connector
CN13
Audio jack
LD7
ST-LINK/V2-1
COM LED
B2
Tamper
Button
B1
Reset Button
4color
LEDs
RV3
Potentiometer
RV2
VDD_Adjustment
CN16
Power Jack
U14
IrDA
U4
STM32F091VCT6
CN6, CN7
Extension
header
CN10
SWD connector
CN1
8x USARTs
connector
CN4
HDMI
Source
D8
IR receiver
LD6
IR LED
CN8
PicroSD card
B3
Joystick
CN9
RS232/RS485
TS1, TS2
Touch Buttons
Lowvoltage
alarm LEDs
CN5
CAN
R1
LDR
LD10
USB Over
Current

Hardware layout and configuration UM1817
10/58 DocID026902 Rev 3
Figure 4. Mechanical dimensions
Table 1. Mechanical dimensions
Symbol Size (mm) Symbol Size (mm) Symbol Size (mm)
A 68.58 e 77.44 P1 26.67
a1 2.54 H 11 P2 111.76
a2 2.54 Lx 5.715 Q1 24.12
B 36 Ly 5.715 Q2 17.70
D 3.5 Mx 19.08 X 114.3
d 3.2 My 23.81 Y 172.72

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UM1817 Hardware layout and configuration
57
2.1 Embedded ST-LINK/V2-1
The ST-LINK/V2-1 programming and debugging tool is integrated on the STM32091C-EVAL
evaluation board. Compared to ST-LINK/V2 the changes are listed below.
The new features supported on ST-LINK/V2-1 are:
•USB software re-enumeration
•Virtual COM port interface on USB
•Mass storage interface on USB
•USB power management request for more than 100 mA power on USB
This feature is no more supported on ST-LINK/V2-1:
•SWIM interface
For all general information concerning debugging and programming features common
between V2 and V2-1 refer to the ST-LINK/V2 in-circuit debugger/programmer for STM8
and STM32ST-LINK/V2 User manual (UM1075).
Note: It is possible to power the board via CN12 (Embedded ST-LINK/V2-1 USB connector) even
if an external tools is connected to CN10 (High density SWD connector) or CN11 (SWD
connector).
2.1.1 Drivers
The ST-LINK/V2-1 requires a dedicated USB driver, which can be found at the www.st.com
website for Windows®7 and 8. On Windows®XP the ST-LINK/V2-1 driver requires WinUsb
to be installed before using the ST-LINK/V2-1 (either available from Microsoft website or
included in the USB driver for ST-LINK/V2 for XP).
In case the STM32091C-EVAL evaluation board is connected to the PC before the driver is
installed, some STM32091C-EVAL interfaces may be declared as “Unknown” in the PC
device manager. In this case the user must install the driver files, and update the driver of
the connected device from the device manager.
Note: Prefer using the “USB Composite Device” handle for a full recovery.
Figure 5. USB Composite Device

Hardware layout and configuration UM1817
12/58 DocID026902 Rev 3
2.1.2 ST-LINK/V2-1 firmware upgrade
The ST-LINK/V2-1 embeds a firmware upgrade mechanism for in-situ upgrade through the
USB port. As the firmware may evolve during the life time of the ST-LINK/V2-1 product (for
example new functionalities, bug fixes, support for new microcontroller families), it is
recommended to visit the www.st.com website before starting to use the STM32091C-EVAL
board and periodically, in order to stay up-to-date with the latest firmware version.
2.2 Board power supply
STM32091C-EVAL evaluation board is designed to be powered by 5 V DC power supply
and to be protected by PolyZen from wrong power plug-in event. It is possible to configure
the evaluation board to use any of the following three sources for the power supply:
•5 V DC power adapter connected to CN16 (the Power jack on the board showed as
PSU on JP15 silkscreen and called E5V). The external power supply is not provided
with the board.
•5 V DC power from CN12 (the USB Type-B connector of ST-LINK/V2-1, that is showed
as STlk on JP15 silkscreen and called U5V). If the USB enumeration succeeds (as
explained below), the ST-LINK U5V power is enabled, by asserting the PWR_EN pin.
This pin is connected to a power switch (ST890), which powers the board. This power
switch features also a current limitation to protect the PC in case of short-circuit on the
board. If overcurrent (more than 600 mA) happens on board, the LED LD10 is lit.
•5 V DC power from CN7 (the extension connector for daughterboard, that is showed as
D5V on JP15 silkscreen).
STM32091C-EVAL evaluation board can be powered from ST-LINK USB connector CN12
(U5V), but only the ST-LINK part has the power before USB enumeration, because the host
PC only provides 100 mA to the board at that time. During the USB enumeration, the
STM32091C-EVAL board asks for the 300 mA power to the host PC. If the host is able to
provide the required power, the enumeration finishes by a “SetConfiguration” command and
then, the power transistor U23 (ST890) is switched ON, the red LED LD5 is turned ON, thus
STM32091C-EVAL board can consume maximum 300 mA current, but not more. If the host
is not able to provide the requested current, the enumeration fails. Therefore the ST890
(U23) remains OFF and the STM32 part including the extension board will not be powered.
As a consequence the red LED LD5 remains turned OFF. In this case it is mandatory to use
an external power supply as extra power supply.
E5V (from PSU) or D5V can be used as external power supply in case the current
consumption of the STM32091C-EVAL board exceeds the allowed current on the USB. In
this condition it is still possible to use the USB for communication, for programming or
debugging only, but it is mandatory to power the board first using E5V or D5V, then
connecting the USB cable to the PC. Proceeding this way the enumeration succeeds thanks
to the external power source.
The following power sequence procedure must be respected:
4. Connect jumper JP15 for PSU or D5V side
5. Check that JP18 is removed
6. Connect the external power source to PSU or D5V (daughterboard mounted)
7. Check red LED LD5 is turned ON
8. Connect the PC to USB connector CN12

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UM1817 Hardware layout and configuration
57
If this order is not respected, the board may be powered by VBUS first then E5V or D5V,
and the following risks may be encountered:
1. If more than 300 mA current is needed by the board, the PC may be damaged or
current can be limited by PC. As a consequence the board is not powered correctly.
2. 300 mA is requested at enumeration (since JP18 must be OFF), so there is risk that the
request is rejected and the enumeration does not succeed if the PC cannot provide
such current. Consequently the board is not powered (LED LD5 remains OFF).
Note: In case the board is powered by a USB charger, there is no USB enumeration, so the led
LD5 remains set to OFF permanently and the board is not powered. Only in this specific
case the jumper JP18 needs to be set to ON, to allow the board to be powered anyway.
Figure 6 helps to understand the structure of the power source on the evaluation board.
Figure 6. Structure of the power source
The power source is selected by setting the related jumpers JP15, JP7 and JP10 as
described in Table 2.
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Hardware layout and configuration UM1817
14/58 DocID026902 Rev 3
Table 2. Power source related jumpers
Jumper Description
JP15
JP15 is used to select one of the three possible power supply resources. For
power supply jack (CN16) to the STM32091C-EVAL only, JP15 is set as
shown to the right:
For power supply from the daughterboard connectors (CN7) to STM32091C-
EVAL only, JP15 is set as shown to the right:
For power supply from USB (CN12) of ST-LINK/V2-1 to STM32091C-EVAL only,
JP15 is set as shown to the right: (Default Setting)
For power supply from power supply jack (CN16) to both STM32091C-EVAL
and daughterboard connected on CN6 and CN7, JP15 is set as shown to the
right (daughterboard must not have its own power supply connected)
JP7
The Vbat pin of STM32F091VCT6 is connected to VDD when JP7 is set as
shown to the right (Default setting):
The Vbat pin of STM32F091VCT6 is connected to the 3 V battery when JP7 is
set as shown to the right:
JP10
The VDDIO2 pin of STM32F091VCT6 is connected to 3.3V when JP10 is set as
shown to the right (Default setting):
The VDDIO2 pin of STM32F091VCT6 is connected to VDD_ADJ when JP10 is
set as shown to the right:
PSU D5V STlk
PSU D5V STlk
PSU D5V STlk
PSU D5V STlk
1 2 3
1 2 3
1 2 3
1 2 3

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UM1817 Hardware layout and configuration
57
2.3 STM32 power-mode configuration
Total three power modes are supported on the board that are configured by setting the
related jumpers JP5, JP6, JP8, JP9 and JP12 as described in Table 3 and in the Notes
below.
•Mode1: The VDD and VDDA are connected together and powered by fixed 3.3 V.
•Mode2: The VDD and VDDA are connected together and powered by adjustable
voltage from 1.65 V to 3.6 V.
•Mode3: The VDD is powered by adjustable voltage from 1.65 V to 3.6 V while VDDA is
powered by fixed 3.3 V.
Note:1 JP8 allows current measurement on VDD_MCU. Current measurement is performed by
replacing JP8 by an ammeter.
Note:2 JP12 allows current measurement on VDDIO2. Current measurement is performed by
replacing JP12 by an ammeter.
Note:3 JP6 allows to connect analog power source VDD_ANA to the STM32 VDDA. JP6 must be
opened (to disconnect VDDA from all analog power VDD_ANA which is connected to
analog circuits on the board) for STM32 Idd measurement.
Note:4 LD8 is lit when VDD < 2V and in this case STM32 is not functional. LD9 is lit when
VDDA < 2.4 V and in this case analogue parts in STM32F091VCT6 are not functional.
The LED LD5 is lit when the STM32091C-EVAL evaluation board is powered by the 5 V
correctly.
Table 4 shows the low-voltage limitations that might apply depending on the characteristics
of some peripheral components. Components might work incorrectly when the power level
is lower than the limitation.
Table 3. Power mode related jumpers
Power mode
Power mode configuration VDD_MCU Idd
measurement
(On JP8)
JP9 JP5
Mode1
OK
NOT allowed
Mode2 OK
Mode3 NOT allowed
1 2 3
1 2 3
1 2 3
1 2 3
1 2 3
1 2 3
1 2 3
1 2 3

Hardware layout and configuration UM1817
16/58 DocID026902 Rev 3
CAUTION:
1. JP8 and JP12 are not allowed to be opened; otherwise STM32F091VCT6 would be
damaged due to a lack of power supply on its power pins.
2. Risk of explosion if battery is replaced by an incorrect type. Dispose of used batteries
according to the instructions.
2.4 Clock source
Two clock sources are available on the STM32091C-EVAL evaluation board for
STM32F091VCT6 and RTC embedded.
•X1, 32 KHz crystal for embedded RTC
•X2, 8 MHz crystal with socket for STM32F091VCT6 microcontroller, it can be removed
from socket when internal RC clock is used.
See Table 5 and Table 6.
Table 4. Low-voltage limitation
Peripheral Component IO name Low-voltage limitation
Audio amplifier U18 Audio input 2.2 V (VDDA)
Microphone amplifier U15 Audio output 2.7 V (VDDA)
CAN CN5 CAN 3 V (VDDIO2)
Smartcard CN19 USART2 2.7 V (VDD)
Table 5. 32 KHz crystal X1 related solder bridges
Jumper Description
SB11
PC14 is connected to the 32KHz crystal when SB11 is open.
(Default setting)
PC14 is connected to extension connector CN6 when SB11 is closed. In such case
R54 must be removed to avoid disturbance due to the 32 Khz quartz.
SB12
PC15 is connected to the32 KHz crystal when SB12 is open.
(Default setting)
PC15 is connected to extension connector CN6 when SB12 is closed. In such case
R55 must be removed to avoid disturbance due to the 32 Khz quartz.
Table 6. 8MHz crystal X2 related solder bridges
Jumper Description
SB13
PF0 is connected to the 8 MHz crystal when SB13 is open.
(Default setting)
PF0 is connected to the extension connector CN7 when SB13 is closed. In such
case C18 and X2 must be removed.

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UM1817 Hardware layout and configuration
57
2.5 Reset source
The reset signal of STM32091C-EVAL evaluation board is low active and the reset sources
include:
•Reset button B1
•Debugging tools from SWD connector CN10 and CN11
•Daughterboard from CN7
•Embedded ST-LINK/V2-1
•RS-232 connector CN9 for ISP.
Note: The jumper JP11 must be closed for RESET handled by pin 8 of the RS-232 connector CN9
(CTS signal). Refer to Section 2.8 for details.
2.6 Boot option
The STM32091C-EVAL evaluation board is able to boot from:
•Embedded user Flash
•System memory with boot loader for ISP
•Embedded SRAM for debugging
The boot option is configured by setting one jumper cap on CN7 between pin 22 and pin 24
and one option bit (see Table 7).
The BOOT0 can also be configured via RS-232 connector CN9, as shown in Table 8.
SB14
PF1 is connected to 8MHz crystal when SB14 is open.
(Default setting)
PF1 is connected to extension connector CN7 when SB14 is closed. In such case
R56 must be removed to avoid disturbance due to the 8 Mhz quartz.
Table 6. 8MHz crystal X2 related solder bridges (continued)
Table 7. Boot related switch
Switch
configuration
bit12 in USER
OPTION BYTES Boot from
CN7 pin 22 and
pin 24 opened X STM32091C-EVAL boot from User Flash. (Default setting)
CN7 pin 22 and
pin 24 closed by
jumper
0 STM32091C-EVAL boot from Embedded SRAM.
CN7 pin 22 and
pin 24 closed by
jumper
1 STM32091C-EVAL boot from System Memory.

Hardware layout and configuration UM1817
18/58 DocID026902 Rev 3
2.7 Audio
STM32091C-EVAL evaluation board supports stereo audio playback and microphone
recording by an external headset connected on audio jack CN13. Audio play is connected to
DAC output of the STM32F091VCT6 through an audio amplifier and microphone on
headset is connected to ADC input of the STM32F091VCT6 through a microphone
amplifier. Audio amplifier is enabled or disabled by setting JP17 and mono/stereo playback
is selected by setting JP14, refer to Table 9 for details.
Audio amplifier operates correctly when VDDA > 2.2V and microphone amplifier operates
correctly when VDDA > 2.7V.
2.8 RS-232, RS-485 and IrDA
The RS-232 (with hardware flow control CTS and RTS), the RS-485 and the IrDA
communication are supported by the D-type 9-pins RS-232/RS-485 connectors CN9, and
by the IrDA transceiver U14 which is connected to the USART1 of the STM32F091VCT6 on
the STM32091C-EVAL evaluation board. The signal Bootloader_RESET (shared with CTS
signal) and the Bootloader_BOOT0 (shared with DSR signal) are added on the RS-232
connector CN9 for ISP support.
USART1_Rx is chosen by setting of JP13, refer to Table 10 for details.
Table 8. Boot0 related jumpers
Jumper Description
JP4
The Bootloader_BOOT0 is managed by pin 6 of the connector CN9 (RS-232 DSR
signal) when JP4 is closed. This configuration is used for the bootloader application
only.
Default Setting: Not fitted
Table 9. Audio related jumpers
Jumper Description
JP17
Speaker amplifier U18 is enabled when JP17 is closed (Default setting)
Speaker amplifier U18 is disabled when JP17 is open
JP14
Mono playback is enabled when JP14 is set as shown to the right (Default setting):
Stereo playback is enabled when JP14 is set as shown to the right:
1 2 3
1 2 3

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UM1817 Hardware layout and configuration
57
The RS-485 communication is supported by the RS-485 transceiver ST3485EBDR which is
connected to pin 4 and pin 9 of D-type 9-pins connectors CN9 (share same connector with
USART1), see Table 11.
2.9 Touch sensing buttons
Two touch sensing buttons are supported on the STM32091C-EVAL evaluation board and
they are connected to three capacitive sensing channels (PD[12:14]) in group8 with active
shield being connected to two capacitive sensing channels (PB11 and PB12) in group6 (see
Table 12).
Table 10. RS-232 and IrDA related jumpers
Jumper Description
JP13
RS232_RX is connected to RS-232 transceiver and RS-232 communication is
enabled when JP13 is set as shown to the right (Default setting):
RS485_RX is connected to RS-485 transceiver and RS-485 communication is
enabled when JP13 is set as shown to the right:
IrDA_RX is connected to IrDA transceiver and IrDA communication is enabled when
JP13 is set as shown to the right:
Table 11. RS-485 related solder bridges
Jumper Description
SB15, SB18
The external failsafe biasing are enabled when solder bridges SB15 and SB18 are
closed
Default Setting: Not fitted
SB19 The bus termination is enabled when solder bridge SB19 is closed.
Default Setting: Not fitted
SB16
The AC termination is disabled when solder bridge SB16 is closed for high baud rate
communication.
Default Setting: Not fitted
RS232 RS485 IrDA
RS232 RS485 IrDA
RS232 RS485 IrDA

Hardware layout and configuration UM1817
20/58 DocID026902 Rev 3
Note: Touch sensing buttons are fully functional only when the STM32091C-EVAL board is
powered on in power mode 1 (both VDD and VDDA are connected to fixed 3.3 V). It is
potentially necessary to adjust the capacitor value of C8 and the firmware to adapt them to
the voltage range from 1.65 V to 3.6 V of VDD on power-mode 2 and 3.
2.10 microSD card
The 2-Gbyte (or more) microSD card connected to SPI1 port (Shared with color LCD) of the
STM32F091VCT6 is available on the board. microSD card detection is managed by
standard IO port PE11 and it should be set with internal pull-up.
2.11 Analog input
The two-pin header CN18 and the 10K ohm potentiometer RV3 are connected to PC0 of
STM32F091VCT6 as analog input. A low-pass filter is implemented by replacing R191 and
C101 with the right value of resistor and capacitor as requested by end user’s application.
Table 12. Touch sensing buttons related solder bridges
Solder Bridge Description
SB7
PD13 is connected to touch slider when SB7 is open.
(Default setting)
PD13 is connected to extension connector CN7 when SB7 is closed. In such case
R24 must be removed to avoid disturbance due to the touch button.
SB8
PD12 is connected to touch slider when SB8 is open.
(Default setting)
PD12 is connected to extension connector CN7 when SB8 is closed. In such case
R25 must be removed to avoid disturbance due to the touch button.
SB6
PD14 is connected to sampling capacitor when SB6 is open.
(Default setting)
PD14 is connected to extension connector CN7 when SB6 is closed. In such case
C4 must be removed to avoid disturbance due to the capacitor.
SB9
PB12 is connected to shield when SB9 is open.
(Default setting)
PB12 is connected to extension connector CN6 when SB9 is closed. In such case
R30 must be removed to avoid disturbance due to the shield.
SB10
PB11 is connected to shield charge capacitor when SB10 is open.
(Default setting)
PB11 is connected to extension connector CN6 when SB10 is closed. In such case
R37 must be removed to avoid disturbance due to the capacitor.