OLIMEX AVR-T32U4 User manual

AVR-T32U4 development breadboard
USER’S MANUAL
Document revision C, February 2014
Designed by OLIMEX Ltd, 2012
All boards produced by Olimex LTD are ROHS compliant

OLIMEX© 014 AVR-T3 U4 user's manual
© 014 Olimex Ltd. Olimex®, logo and combinations thereof, are registered trademarks of Olimex Ltd. Other product
names may be trademarks of others and the rights belong to their respective owners.
he information in this document is provided in connection with Olimex products. No license, express or implied
or otherwise, to any intellectual property right is granted by this document or in connection with the sale of
Olimex products.
This work is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported License. To view a copy of
this license, visit http://www.creativecommons.org/licenses/by-sa/3.0/.
This hardware design by Olimex LTD is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported
License.
The software is released under GPL.
It is possible that the pictures in this manual differ from the latest revision of the board.
The product described in this document is subject to continuous development and improvements. All particulars of the
product and its use contained in this document are given by OLIMEX in good faith. However all warranties implied or
expressed including but not limited to implied warranties of merchantability or fitness for purpose are excluded. This
document is intended only to assist the reader in the use of the product. OLIMEX Ltd. shall not be liable for any loss or
damage arising from the use of any information in this document or any error or omission in such information or any
incorrect use of the product.
This evaluation board/kit is intended for use for engineering development, demonstration, or evaluation purposes only
and is not considered by OLIMEX to be a finished end-product fit for general consumer use. Persons handling the
product must have electronics training and observe good engineering practice standards. As such, the goods being
provided are not intended to be complete in terms of required design-, marketing-, and/or manufacturing-related
protective considerations, including product safety and environmental measures typically found in end products that
incorporate such semiconductor components or circuit boards.
Olimex currently deals with a variety of customers for products, and therefore our arrangement with the user is not
exclusive. Olimex assumes no liability for applications assistance, customer product design, software performance, or
infringement of patents or services described herein.
HERE IS NO WARRAN Y FOR HE DESIGN MA ERIALS AND HE COMPONEN S
USED O CREA E AVR- 32U4. HEY ARE CONSIDERED SUI ABLE ONLY FOR AVR-
32U4
Page of 9

OLIMEX© 014 AVR-T3 U4 user's manual
Table of Contents
CHAPTER OVERVIEW ......................................................................................... 5
1. Introduction to the chapter .................................................................................................. 5
1.1 Features ................................................................................................................................ 5
1.2 Similar boards ..................................................................................................................... 5
1.3 Organization ........................................................................................................................ 5
Chapter 2 Introduction to arduino/pinguino/maple ................................................. 7
2. What is Arduino? .................................................................................................................. 7
2.1 First steps with Arduino IDE ............................................................................................. 8
2.1.1 For purchases after the official release of Leonardo ..................................................... 8
2.1.2 For purchases before the official release of Leonardo .................................................. 8
CHAPTER 3 SETTING UP THE AVR-T32U4 BOARD ....................................... 0
3. Introduction to the chapter ................................................................................................ 10
3.1 Electrostatic warning ........................................................................................................ 10
3.2 Requirements ..................................................................................................................... 10
3.3 Powering the board ........................................................................................................... 11
3.4 Prebuilt software ............................................................................................................... 12
CHAPTER 4 AVR-T32U4 BOARD DESCRIPTION ............................................. 3
4. Introduction to the chapter ................................................................................................ 13
4.1 Layout (top view) .............................................................................................................. 13
4.2 Layout (bottom view) ........................................................................................................ 14
CHAPTER 5 THE ATMEGA32U4 MICROCONTROLLER .............................. 5
5. Introduction to the chapter ................................................................................................ 15
5.1 he micro-controller’s features ........................................................................................ 15
6. Introduction to the chapter ................................................................................................ 17
6.1 Reset ................................................................................................................................... 17
6.2 Clock ................................................................................................................................... 17
CHAPTER 7 HARDWARE ...................................................................................... 8
7. Introduction to the chapter ................................................................................................ 18
7.1 ICSP pin holes .................................................................................................................... 18
7.2 UEX .................................................................................................................................. 18
7.4 Extension pins .................................................................................................................... 19
7.5 USB mini connector .......................................................................................................... 20
7.7 Jumper description ........................................................................................................... 20
7.9 Additional hardware components .................................................................................... 21
CHAPTER 8 MEMORY AND BLOCK DIAGRAM ............................................. 22
8. Introduction to the chapter ................................................................................................ 22
8.1 Memory organization ....................................................................................................... 23
Page 3 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
CHAPTER 9 SCHEMATICS ................................................................................... 24
9. Introduction to the chapter ................................................................................................ 24
9.1 Eagle schematic ................................................................................................................. 24
9.2 Physical dimensions .......................................................................................................... 26
CHAPTER 0 REVISION HISTORY ..................................................................... 27
10. Introduction to the chapter .............................................................................................. 27
10.1 Document revision ........................................................................................................... 27
10.2 Web page of your device ................................................................................................. 28
8.3 Product support ................................................................................................................. 29
Page 4 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
CHAPTER OVERVIEW
. Introduction to the chapter
Thank you for choosing the AVR-T3 U4 development board from Olimex! This document provides
a User’s Guide for the Olimex AVR-T3 U4 development board. As an overview, this chapter gives
the scope of this document and lists the board’s features. The document’s organization is then
detailed.
The AVR-T3 U4 development board enables code development of applications running on the
ATMega3 U4 microcontroller, manufactured by Microchip technology.
. Features
Some of the features of the board are listed below:
•ATMEGA3 U4 microcontroller, all in one USB communication no need for external FTDI
chip.
•Input power supply taken from mini USB
•Feeds power to the breadboard bus
•Works both on 3.3V and 5V
•UEXT connector which allow many existing modules like RF, ZIGBEE, GSM, GPS to be
connected
•The LEDs and the BUTTONs are on the edge of the board so there is easy access even if the
boards have shields on them
•Mini USB connector is used which is common and used in most cell phones, so you do not
have to buy other cables
.2 Similar boards
AVR-T3 U4 is ARDUINO-LEONARDO-like breadboard with ATMega3 U4.
It is a powerful board considering its low price but yet a starter board for the Arduino family.
The more powerful Arduino boards we have in the range are OLIMEXINO-3 U4 again based on
Leonardo and OLIMEXINO-3 8 – based on Arduino Duenomilanove. Both differ from AVR-
T3 U4 in having the standard Arduino shield connectors and additional features. OLIMEXINO-3 8
has a more sophisticated supply circuit, USB OTG connector and there are more Arduino projects
available for it.
.3 Organization
Each section in this document covers a separate topic, organized as follow:
–Chapter 1 is an overview of the board usage and features
–Chapter has a short introduction to Arduino platform and its derivatives Pinguino and
Page 5 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
Maple
–Chapter 3 provides a guide for quickly setting up the board
–Chapter 4 contains the general board diagram and layout
–Chapter 5 describes the component that is the heart of the board: the ATMega3 U4
microcontroller
–Chapter 6 is an explanation of the control circuitry associated with the microcontroller to
reset. Also shows the clocks on the board
–Chapter 7 covers the connector pinout, peripherals and jumper description
–Chapter 8 shows the processor diagram and memory map
–Chapter 9 provides the schematics
–Chapter 10 contains the revision history
Page 6 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
CHAPTER 2 INTRODUCTION TO ARDUINO/PINGUINO/MAPLE
2. What is Arduino?
Arduino is an open-source electronics prototyping platform, designed to make the process of using
electronics in multidisciplinary projects easily accessible. The hardware consists of a simple open
hardware design for the Arduino board with an Atmel AVR processor and on-board I/O support. The
software consists of a standard programming language and the boot loader that runs on the board.
Arduino hardware is programmed using a Wiring-based language (syntax + libraries), similar to C+
+ with some simplifications and modifications, and a Processing-based Integrated Development
Environment (IDE).
The project began in Ivrea, Italy in 005 aiming to make a device for controlling student-built
interaction design projects less expensively than other prototyping systems available at the time. As
of February 010 more than 1 0,000 Arduino boards had been shipped. Founders Massimo Banzi
and David Cuartielles named the project after a local bar named Arduino. The name is an Italian
masculine first name, meaning "strong friend". The English pronunciation is "Hardwin", a
namesake of Arduino of Ivrea.
More information could be found at the creators web page http://arduino.cc/ and in the Arduino
Wiki http://en.wikipedia.org/wiki/Arduino
To make the story short - Arduino is easy for beginners who lack Electronics knowledge, but also
does not restrict professionals as they can program it in C++ or mix of Arduino/C++ language.
There are thousands of projects which makes it easy to startup as there is barely no field where
Arduino enthusiasts to have not been already.
Arduino has inspired two other major derivates - MAPLE and PINGUINO. Based on 8-bit AVR
technology the computational power of Arduino boards is modest, this is why a team from MIT
developed the MAPLE project which is based on ARM7 STM3 F103RBT6 microcontroller. The
board has same friendly IDE as Arduino and offers the same capabilities as hardware and software
but runs the Arduino code much faster. The Maple project can be found at http://leaflabs.com
In parallel with Arduino another project was started called PINGUINO. This project chose its first
implementation to be with PIC microcontrollers, as AVRs were hard to find in some parts of the
world like South America so it is likely to see lot of PINGUINO developers are from that part of the
world. PINGUINO project founders decided to go with Python instead Java for processing
language. For the moment PINGUINO is much more flexible than Arduino as it is not limited to
8bit microcontrollers. Currently the IDE, which has GCC in background, can support 8-bit PIC
microcontrollers, 3 bit PIC3 (MIPS) microcontrollers and ARM7/CORTEXM3 microcontrollers
which makes PINGUINO very flexible because once you make your project you can migrate easily
through different hardware platforms and not being bound to a single microcontroller manufacturer.
The PINGUINO project can be found at: http://www.pinguino.cc.
Page 7 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
2. First steps with Arduino IDE
Depending when you purchased the board there are two scenarios since the PID (product ID) which
is stored in the firmware and expected by the IDE is different between versions 1.0.0 and 1.0.1
(1.0.1 is the first release of the Arduino IDE with official support for Leonardo).
2. . For purchases after the official release of Leonardo
Boards produced after the official release of Arduino Leonardo have the latest bootloader available
with the adjusted bootloader PID. Download the latest Arduino IDE and extract the package. You
can find the needed driver for the bootloader located in folder /drivers. You click update on the
device in device manager and point the installer to the /drivers folder.
Then launch Arduino IDE and set the correct board and COM port in TOOLS menu.
From File->Open navigate to the examples folder which is found in the Arduino IDE installation
folder. Choose a simple example to begin with like BlinkWithoutDelay.ino and open it. Click verify
and after it compiles click “Upload”. Voila, you have uploaded code to your Arduino device.
Now start exploring the world of Arduino! More info and help on the software can be found and the
official Arduino web site: http://www.arduino.cc/.
2. .2 For purchases before the official release of Leonardo
If you have purchased the T-3 U4 before the official release of the Arduino Leonardo board there
are two scenarios for using Arduino IDE:
1) Download Arduino IDE 1.0 RC or Arduino IDE 1.0.0. When you extract the package check if
the Arduino Leonardo section is the \hardware\arduino\boards is uncommented. If the section has
number signs (#) infront remove the number signs (#).
) If you want to use the latest version (which by the time of writing is 1.0.1) you would need to
change to bootloader firmware. This will require an AVR programmer tool.
You can get the bootloader in .elf format from our web site. You can also use the original bootloader
hex if you set the fuses and lock bits for the processor as follows:
low_fuses=0xff
high_fuses=0xd8
extended_fuses=0xcb
lock_bits (choose “SPM Prohibited in Boot Section”) from the drop down menu which will set the
bits either to EF or F.
Page 8 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
After you have downloaded and extracted the desired IDE you need to install the driver for your
operating system. You can find the needed driver for the bootloader located in folder /drivers. You
click update on the device in device manager and point the installer to the /drivers folder.
Then launch Arduino IDE and set the correct board and COM port in TOOLS menu.
From File->Open navigate to the examples folder which is found in the Arduino IDE installation
folder. Choose a simple example to begin with like BlinkWithoutDelay.ino and open it. Click verify
and after it compiles click “Upload”. Voila, you have uploaded code to your Arduino device.
Now start exploring the world of Arduino! More info and help on the software can be found and the
official Arduino web site: http://www.arduino.cc/.
Page 9 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
CHAPTER 3 SETTING UP THE AVR-T32U4 BOARD
3. Introduction to the chapter
This section helps you set up the AVR-T3 U4 development board for the first time.
Please consider first the electrostatic warning to avoid damaging the board, then discover the
hardware and software required to operate the board.
The procedure to power up the board is given, and a description of the default board behavior is
detailed.
3. Electrostatic warning
AVR-T3 U4 is shipped in a protective anti-static package. The board must not be exposed to high
electrostatic potentials. A grounding strap or similar protective device should be worn when
handling the board. Avoid touching the component pins or any other metallic element.
3.2 Requirements
In order to set up the AVR-T3 U4, the following items are required:
If using the free ARDUINO IDE the ONLY requirement is a miniUSB to USB-A cable to connect
to a computer.
Since this is a board mainly focused on breadboarding having a breadboard is highly advisable. This
way you can have access to the free pins using jumper wires and no need of pesky soldering and
unsoldering! Good and cheap choices are the ones we offer:
BREADBOARD-1 - 8 x5 x10 mm solderless breadboard for experimenting
BREADBOARD–MINI - 45x35x8.5 mm solderless breadboard for experimenting
On the next page you can find a picutre of AVR-T3 U4 mounted on a breadboard.
Page 10 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
If you want to upgrade the bootloader, or program the board without the ARDUINO-IDE there are
pinouts for ICSP programmer (note that there IS a 6-pin connector mounted). You can use our AVR-
ISP-ISO, or AVR-ISP-TINY programmer for custom programming without ARDUINO IDE.
Having an AVR programmer is highly advisable since the bootloader software is still not perfect
and it is possible to destroy it only by software means (for instance disabling all interrupts and then
entering infinite loop would hang the bootloader) which would require reinstalling the bootloader.
3.3 Powering the board
The AVR-T3 U4 board is self-powered by the miniUSB if it is connected to a USB hub of a
computer.
Alternatively it can be powered via the power pins located at the bottom of the board. You may
provide between 3.0V and 5V on one of those proto power pins to power the board. Additionally, if
the board is powered by USB you might find 3.3V out on those same pins. Please check the picture
above - the lines that might be used for powering connect at the breadboard at the “+” and “-” lines.
IMPOR AN – DO NO POWER AVR- 32U4 FROM BO H HE USB AND HE PRO O
POWER PINS SIMUL ANEOUSLY. HIS WOULD LEAD O SHOR CIRCUI OR
OVERVOL AGE!
The bootloader starts automatically.
On powering the board PWR_LED should turn on. RXLED and TXLED should turn on and
Page 11 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
monitor the send receive on the virtual COM port.
3.4 Prebuilt software
The board comes with prebuilt ARDUINO bootloader. The different part between the other
Arduinos and Leonardo is that Leonardo doesn't use FTDI chip nor external chip for the virtual
COM port but it is handled by the ATMega3 U4.
Page 1 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
CHAPTER 4 AVR-T32U4 BOARD DESCRIPTION
4. Introduction to the chapter
Here you get acquainted with the main parts of the board. Note the names used on the board differ
from the names used to describe them. For the actual names check the AVR-T3 U4 board itself.
4. Layout (top view)
Page 13 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
4.2 Layout (bottom view)
Page 14 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
CHAPTER 5 THE ATMEGA32U4 MICROCONTROLLER
5. Introduction to the chapter
In this chapter is located the information about the heart of AVR-T3 U4 – its microcontroller. The
information is a modified version of the datasheet provided by its manufacturers.
5. The micro-controller’s features
As per Atmel's datashet:
• High Performance, Low Power AVR® 8-Bit Microcontroller
• Advanced RISC Architecture
– 135 Powerful Instructions – Most Single Clock Cycle Execution
– 3 x 8 General Purpose Working Registers
– Fully Static Operation
– Up to 16 MIPS Throughput at 16 MHz
– On-Chip -cycle Multiplier
• Non-volatile Program and Data Memories
– 3 K Bytes of In-System Self-Programmable Flash
– .5K Bytes Internal SRAM
– 1K Bytes Internal EEPROM
– Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
– Data retention: 0 years at 85°C/ 100 years at 5°C(1)
– Optional Boot Code Section with Independent Lock Bits
In-System Programming by On-chip Boot Program
True Read-While-Write Operation
All supplied parts are preprogramed with a default USB bootloader
– Programming Lock for Software Security
• JTAG (IEEE std. 1149.1 compliant) Interface
– Boundary-scan Capabilities According to the JTAG Standard
– Extensive On-chip Debug Support
– Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG
Interface
• USB .0 Full-speed/Low Speed Device Module with Interrupt on Transfer Completion
– Complies fully with Universal Serial Bus Specification Rev .0
– Supports data transfer rates up to 1 Mbit/s and 1.5 Mbit/s
– Endpoint 0 for Control Transfers: up to 64-bytes
– 6 Programmable Endpoints with IN or Out Directions and with Bulk, Interrupt or
Isochronous Transfers
– Configurable Endpoints size up to 56 bytes in double bank mode
– Fully independent 83 bytes USB DPRAM for endpoint memory allocation
– Suspend/Resume Interrupts
– CPU Reset possible on USB Bus Reset detection
– 48 MHz from PLL for Full-speed Bus Operation
– USB Bus Connection/Disconnection on Microcontroller Request
– Crystal-less operation for Low Speed mode
Page 15 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
• Peripheral Features
– On-chip PLL for USB and High Speed Timer: 3 up to 96 MHz operation
– One 8-bit Timer/Counter with Separate Prescaler and Compare Mode
– Two 16-bit Timer/Counter with Separate Prescaler, Compare- and Capture Mode
– One 10-bit High-Speed Timer/Counter with PLL (64 MHz) and Compare Mode
– Four 8-bit PWM Channels
– Four PWM Channels with Programmable Resolution from to 16 Bits
– Six PWM Channels for High Speed Operation, with Programmable Resolution from
to 11 Bits
– Output Compare Modulator
– 1 -channels, 10-bit ADC (features Differential Channels with Programmable Gain)
–Programmable Serial USART with Hardware Flow Control
–Master/Slave SPI Serial Interface
– Byte Oriented -wire Serial Interface
– Programmable Watchdog Timer with Separate On-chip Oscillator
– On-chip Analog Comparator
– Interrupt and Wake-up on Pin Change
– On-chip Temperature Sensor
• Special Microcontroller Features
– Power-on Reset and Programmable Brown-out Detection
– Internal 8 MHz Calibrated Oscillator
– Internal clock prescaler & On-the-fly Clock Switching (Int RC / Ext Osc)
– External and Internal Interrupt Sources
– Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby, and
Extended Standby
• I/O and Package
– All I/O combine CMOS outputs and LVTTL inputs
– 6 Programmable I/O Lines
– 44-lead QFN Package, 7x7mm
• Operating Voltages
– .7 - 5.5V
• Operating temperature
– Industrial (-40°C to +85°C)
• Maximum Frequency
– 8 MHz at .7V - Industrial range
– 16 MHz at 4.5V - Industrial range
1
For comprehensive information on the microcontroller visit the Atmel web page for a datasheet.
At the moment of writing the microcontroller datasheet can be found at the following link:
http://www.atmel.com/Images/doc7766.pdf
Page 16 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
CHAPTER 6 CONTROL CIRCUITY
6. Introduction to the chapter
Here you can find information about reset circuit, power circuit and quartz crystal locations.
6. Reset
AVR-T3 U4 reset circuit includes R1 (4.7kΩ ), R13 (330Ω), SD5 (Shottky diode), ATMega3 U4
pin 13 (#RESET) and a RESET button. Note that it also can be found at the ICSP header pin 5 and
test pad RESET.
6.2 Clock
16 MHz quarz crystal Q1 is found at pins 16 and 17 of the processor.
Page 17 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
CHAPTER 7 HARDWARE
7. Introduction to the chapter
In this chapter are presented the connectors that can be found on the board all together with their
pinout. Proto area is shown. Jumpers functions are described. Notes and info on specific peripherals
are presented. Notes regarding the interfaces are given.
7. ICSP pin holes
The 6 pin ICSP header provides interface for custom programming/debugging outside of the
PINGUINO IDE. Note the pin holes have a connector mounted over. The pinout can be found in the
table below. It is important to check the jumper configuration for proper use of the ICSP pin hole .
ICSP pin holes
Pin # Signal name Pin # Signal name
1MISO (PB3) 4MOSI (PB2)
2Vcc 5RESET
3SCK (PB1) 6GND
7.2 UEXT
AVR-T3 U4 board has UEXT connector and can interface Olimex's UEXT modules.
For more information on our UEXT modules please visit:
http://www.olimex.com/O HER/UEX .pdf
Pin # Signal name
1+3.3V
2GND
3TXD
4RXD
5SCL
6SDA
7MISO
8MOSI
9SCK
10 UEXT_#CS
Page 18 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
7.4 Extension pins
For your convenience the pads are named individually near each of them. Please take extra care
about the numbering but consider that there might be offset.
Also note that the board comes with no connectors soldered on the pin holes. Before being able to
connect with a shield you have to solder connecters yourself.
Pad name Signal Pad name Signal
ARE AREF D13(UEXT_#CS) PF /ICP3/CLK0/OC4A
RESET RST D12 PD6/T1/#OC4D/ADC9
#HWB (BUT) PE2/#HWB D11 PB /PCINT /OC0A/OC1C/
#RTS
A5 PF0/ADC0 D10 PB6/PCINT6/OC1B/OC4B/
ADC13
A4 PF1/ADC1 D9 PB5/PCINT5/OC1A/#OC4B/
ADC12
A3 PF4/ADC4/TCK D8 PB4/PCINT4/ADC11
A2 PF5/ADC5/TMS D7 (BOOT_LED_ INT6/AIN0/PE6
A1 PD6/ADC6/TDO D6 PD /T0/OC4D/ADC10
A0 PF /ADC /TDI D5 PC6/OC3A/#OC4A
PD5(TXLED) PD5/XCK/CTS D4 PD4/ICP1/ADC8
D17(MISO) PB3/PDO/PCINT3/M
ISO D3 (SCL) PD0/OC0B/SCL/INT0
D16(MOSI) PB2/PDI/PCINT2/
MOSI D2 (SDA) PD1/SDA/INT1
D15(SCK) PB1/PCINT1/
SCLK D1 (TXD) PD3/TXD1/INT3
D14 PB0/SS/PCINT0 D0 (RXD) PD2/RXD1/INT2
Page 19 of 9

OLIMEX© 014 AVR-T3 U4 user's manual
7.5 USB mini connector
Note that the USB is confiugred only as device.
Pin # Signal name
1+5V
2D-
3D+
4Not connected
5GND
7.7 Jumper description
All jumpers on AVR-T3 U4 are board mounted SMT type. This means you would need to cut or
solder to be able to change the position. You would need basic soldering tools and skills to be able
to change the positions.
7.7.1 Jumper 5V_E
If you close 5V_E then the 3.3V voltage regulator VR1 would be bypassed. 5V from the USB or the
proto powering pins would go directly to the board.
Default state is open.
7.7.2 Jumper R23_E
Controls the SPI SCL 4.7k pull-up resistor. By default the jumper is closed and the resistor is
enabled.
Default position is closed.
7.7.3 Jumper R24_E
Controls the SPI SDA 4.7k pull-up resistor. By default the jumper is closed and the resistor is
enabled.
Default position is closed.
7.7.4 Jumper R25_E
Controls the SPI CS (chip select) 4.7k pull-up resistor. By default the jumper is closed and the
resistor is enabled.
Default state is closed.
Page 0 of 9