Axiom TWR-S12G128 User manual

D O C - 0 508- 0 1 0 , R E V D
Web Site: www.axman.com
Support: [email protected]
TWR-S12G128
Demonstration Board for Freescale MC9S12G128
Microcontroller
USER GUIDE

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CONTENTS
CAUTIONARY NOTES ..............................................................................................................4
TERMINOLOGY.........................................................................................................................4
FEATURES................................................................................................................................5
MEMORY MAP ..........................................................................................................................6
SOFTWARE DEVELOPMENT...................................................................................................6
DEVELOPMENT SUPPORT......................................................................................................7
OSBDM BOOTLOADER........................................................................................................ 7
BDM_PORT HEADER........................................................................................................... 7
POWER......................................................................................................................................8
POWER SELECT.................................................................................................................. 8
RESET SWITCH ........................................................................................................................8
LOW VOLTAGE RESET............................................................................................................8
TIMING.......................................................................................................................................9
COMMUNICATIONS..................................................................................................................9
RS-232.................................................................................................................................. 9
COM CONNECTOR........................................................................................................ 10
COM_EN......................................................................................................................... 10
LIN PORT............................................................................................................................ 11
LIN ENABLE.................................................................................................................... 11
LIN COM INPUT.............................................................................................................. 11
LIN_PWR OPTION.......................................................................................................... 11
MSTR OPTION................................................................................................................ 12
LIN-J1 CONNECTOR...................................................................................................... 12
CAN PORT.......................................................................................................................... 13
CAN TERMINATION ENABLE........................................................................................ 13
STANDBY MODE............................................................................................................ 13
USER PERIPHERALS.............................................................................................................14
POTENTIOMETER.............................................................................................................. 14
USER LED’S ....................................................................................................................... 14
PUSHBUTTON SWITCHES................................................................................................ 14
EDGE CONNECTOR PINOUT.................................................................................................15

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FIGURES
Figure 1: Memory Map................................................................................................................6
Figure 2: BDM_PORT Header....................................................................................................7
Figure 3: PWR_SEL Option Header...........................................................................................8
Figure 4: Serial Connections ....................................................................................................10
Figure 5: COM1 Connector.......................................................................................................10
Figure 6: COM_EN Option Header...........................................................................................10
Figure 7: LIN Block Diagram.....................................................................................................11
Figure 8: JP3 Option Header...................................................................................................12
Figure 9: LIN Connector ...........................................................................................................12
Figure 10: CAN_PORT.............................................................................................................13
Figure 11: CAN Termination Enable.........................................................................................13
Figure 12: JP1 Option Header..................................................................................................14
Figure 13: Primary Edge Connector.........................................................................................15
Figure 14: Secondary Edge Connector ....................................................................................17
REVISION
Date
Rev
Comments
June 2, 2010
A
Initial Release
June 30, 2010
B
Updated / Corrected target MCU memory map. Updated reference to
MC9S12G Family Reference Manual
October 14, 2010
C
Final Updates, removed OSBDM disclaimer
January 4, 2011
D
Minor corrections from customer review

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CAUTIONARY NOTES
1) Electrostatic Discharge (ESD) prevention measures should be used when handling this
product. ESD damage is not a warranty repair item.
2) Axiom Manufacturing does not assume any liability arising out of the application or use of
any product or circuit described herein; neither does it convey any license under patent
rights or the rights of others.
3) EMC Information on the TWR-S12G128 board:
a) This product as shipped from the factory with associated power supplies and cables,
has been verified to meet with requirements of CE and the FCC as a CLASS A product.
b) This product is designed and intended for use as a development platform for hardware
or software in an educational or professional laboratory.
c) In a domestic environment, this product may cause radio interference in which case the
user may be required to take adequate prevention measures.
d) Attaching additional wiring to this product or modifying the products operation from the
factory default as shipped may affect its performance and cause interference with
nearby electronic equipment. If such interference is detected, suitable mitigating
measures should be taken.
TERMINOLOGY
This development module utilizes option select jumpers to configure default board operation.
Terminology for application of the option jumpers is as follows:
Jumper –a plastic shunt that connects 2 terminals electrically
Jumper on, in, or installed = jumper is a plastic shunt that fits across 2 pins and the shunt is
installed so that the 2 pins are connected with the shunt.
Jumper off, out, or idle = jumper or shunt is installed so that only 1 pin holds the shunt, no 2
pins are connected, or jumper is removed. It is recommended that the jumpers be placed
idle by installing on 1 pin so they will not be lost.
Cut-Trace –a circuit trace connection between component pads. The circuit trace may be
cut using a knife to break the default connection. To reconnect the circuit, simply install a
suitably sized 0-ohm resistor or attach a wire across the pads.
Signal names followed by an asterisk (*) denote active-low signals.

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FEATURES
The TWR-S12G128 is a demonstration board for the MC9S12G128 microcontroller; an
automotive, 16-bit microcontroller focused on low-cost, high-performance in a low pin-count
device. The MC9S12G128 provides16-bit wide accesses, without wait states, for all
peripherals and memories. The MC9S12G128 targets automotive applications requiring CAN
or LIN/J2602 communications. Examples include body controllers, occupant detection, etc…
The board is designed to interface to the Freescale Tower System, a modular development
platform which aids in rapid prototyping and tool-reuse. An integrated Open-Source BDM,
software tools, and examples provided with the development board make application
development and debug quick and easy. All MCU signals are available on one or both edge
connectors.
MC9S12G128, 100 LQFP
128K Bytes Flash
4096 Bytes EEPROM
8192 Bytes RAM
25MHz Bus Frequency
Internal Oscillator
SCI, SPI, MSCAN
Integrated Open Source BDM (OSBDM)
BDM_PORT header for external BDM cable support
1 ea. High-Speed CAN Physical Layer Transceiver
1 ea, Enhanced LIN Physical Layer Transceiver
RS-232 Serial Data Physical Layer Transceiver
On-board +5V regulator
Power input from OSBDM, Tower System, or input
vias at E1/E2
Power Input Selection Jumpers
Power input from USB-BDM
Power input from on-board regulator
Power input from Tower System edge connector
User Peripherals
4 User Push Button Switches
4 User LED Indicators
5K ohm POT w /LP Filter
User Option Jumpers to disconnect Peripherals
Connectors
BDM_PORT Connector for External BDM Cable
USB mini-AB Connector
2x5, 0.1” ctr, RS-232 Header
1x4, 4.2mm, Molex CAN Cable Connector
2x2, 4.2mm, Molex LIN Cable Connector
Specifications:
Board Size 3.55” x 3.20” overall
Power Input: +5V from USB connector or from Tower System
NOTE: LIN functionality requires +12V on LIN +V input or +12V at E1/E2 input.

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MEMORY MAP
Figure 1 below shows the target device memory map. Refer to the MC9S12G Family
Reference Manual (RM) for further information.
Figure 1: Memory Map
Address
Module
Size
(Bytes)
0x0000–0x0009
PIM (port integration module)
10
0x000A–0x000B
MMC (memory map control)
2
0x000C–0x000D
PIM (port integration module)
2
0x000E–0x000F
Reserved
2
0x0010–0x0017
MMC (memory map control)
8
0x0018–0x0019
Reserved
2
0x001A–0x001B
Device ID register
2
0x001C–0x001F
PIM (port integration module)
4
0x0020–0x002F
DBG (debug module)
16
0x0030–0x0033
Reserved
4
0x0034–0x003F
CPMU (clock and power management)
12
0x0040–0x006F
TIM0 (timer module)
48
0x0070–0x009F
ATD (analog-to-digital converter, 10 bit, 8-channel)
48
0x00A0–0x00C7
PWM (pulse-width modulator)
40
0x00C8–0x00CF
SCI0 (serial communications interface)
8
0x00D0–0x00D7
SCI1 (serial communications interface)
8
0x00D8–0x00DF
SPI0 (serial peripheral interface)
8
0x00E0–0x00E7
Reserved
8
0x00E8–0x00EF
SCI2 (serial communications interface)
8
0x00F0–0x00F7F
SPI1 (serial peripheral interface)
8
0x00F8–0x00FF
SPI1 (serial peripheral interface)
8
0x0100–0x0113
FTMRG control registers
20
0x0114–0x011F
Reserved
12
0x0120
INT (interrupt module)
1
0x0121–0x013F
Reserved
31
0x0140–0x017F
CAN
64
0x0180–0x023F
Reserved
192
0x0240–0x027F
PIM (port integration module)
64
0x0280–0x02EF
Reserved
112
0x02F0–0x02FF
CPMU (clock and power management)
16
0x0300–0x03FF
Reserved
256
SOFTWARE DEVELOPMENT
Software development requires the use of a compiler or an assembler supporting the
HCS12(X) instruction set and a host PC running a debug interface. CodeWarrior Development
Studio is supplied with this board for application development and debug. Refer to the
supporting CodeWarrior documentation for details on use and capabilities.

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DEVELOPMENT SUPPORT
Application development and debug for the target TWR-S12 board is supported through the
Open-Source Background Debug Mode (OSBDM) interface or an external BDM interface
connector. The OSBDM is fully supported in CodeWarrior and provides direct, non-intrusive
access to the target device internals. While in BDM mode, no internal resources are used.
Code stepping and break-points are fully supported.
Connection between a host PC and the target device is provided via a mini-B, USB connector.
The OSBDM is capable of providing power to the target board eliminating the need for external
power. Please note that power supplied by the OSBDM is limited by the USB specification.
When powered through the OSBDM, total current draw, including the OSBDM, TWR-S12
board, and Tower System must remain less than 500mA. Otherwise, the USB bus will cause
the host PC to disconnect the board. Damage to the host PC, target board, or Tower System
may result if this current limit is violated.
CAUTION:
When powered from the USB bus, do not exceed the 500mA maximum
current drain allowed under the USB specification. Damage to the
target board or host PC may result
OSBDM Bootloader
The OSBDM is pre-programmed with a bootloader application to allow field updates. The USB
bootloader communicates with a GUI application running on a host PC. The GUI application
allows the user to update OSBDM firmware easily and quickly. Option jumper JP401 enables
the bootloader at startup. This option header is not populated in default configuration. Refer
to Freescale Application Note AN3561 for details on using the GUI application and bootloader.
The application note may be found at www.freescale.com or at www.axman.com/support.
BDM_PORT Header
A compatible HCS12 BDM cable can also be attached to the 6-pin BDM interface header at J3.
This header allows the use of external programming/debug cables. Refer to the external
programming/debug cable documentation for details on use. The figure below shows the pin-
out for the DEBUG header.
Figure 2: BDM_PORT Header
J3
BKGD
1
2
GND
See the associated RM for complete DEBUG
documentation
3
4
RESET*
5
6
VDD

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NOTE: This header is not installed in default configuration.
POWER
The TWR-S12 board may be powered from the OSBDM, from the Tower System, from the LIN
+V input, or 2 input vias at E1 & E2. The LIN +V input accepts +12V from the LIN bus and
uses an on-board regulator to create the board operating voltage. Input vias at E1 & E2 allow
connecting external power to the board if desired. An on-board regulator is used to create the
board operating voltage from this input.
Use of the on-board regulator requires input voltage between +7.V and +27V. However, input
voltage should be kept as low as possible to reduce device self-heating.
CAUTION:
This board does not apply reverse polarity protection on inputs E1 &
E2. Polarity for each input is clearly marked. Reverse input polarity
will damage the board.
Power Select
The PWR_SEL option header selects the input power source for the target board. When
powered from the Tower System, the OSBDM voltage output is disabled.
Figure 3: PWR_SEL Option Header
JP5
1
●
●
2
Select TWR voltage input
PWR_SEL
●
●
Select OSBDM voltage input (default)
●
●
Select on-board regulator input
RESET SWITCH
The RESET switch applies an asynchronous RESET input to the MCU. The RESET switch is
connected directly to the RESET* input on the MCU. Pressing the RESET switch applies a
low voltage level to the RESET* input. A pull-up bias resistor allows normal MCU operation.
LOW VOLTAGE RESET
The MC9S12G128 applies an internal Power-On Reset (POR) circuit and an internal Low
Voltage Reset (LVR) circuit to ensure proper device operation. The POR circuit holds the
MCU in reset until applied voltage reaches an appropriate level. The LVR forces the device

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into reset if input voltage falls too low, protecting against brown-out conditions. A user
configurable Low-Voltage Detect (LVD) with interrupt output is also available. Consult the
MC9S12G Family Reference manual for details of POR, LVR, and LVD operation.
TIMING
The TWR-S12G128 internal timing source is active from RESET by default. An external 8MHz
crystal oscillator, configured for low-power operation, is also installed. Refer to the target
device RM for details on selecting and configuring the desired timing source.
COMMUNICATIONS
Communications options for the TWR-S12G128 include serial RS-232, LIN, and CAN. Serial
RS-232 communications is supported through a RS-232 physical layer device (PHY) and a 2x5
pin header. A high-speed, enhanced, LIN PHY provides LIN bus communications through a
2x2 Molex connector (pn 39-29-1048). A high-speed CAN PHY provides CAN bus
communications through a 1 x 4 Molex connector (pn 39-30-3045).
Connecting LIN cables require Molex housing, pn 39-01-2040 and pins, pn 39-00-0217.
Connecting CAN cables require Molex housing, pn 39-01-4040, and pins, pn 39-00-0217.
The COM_SEL option header connects the MCU SCI signal to either the LIN PHY or the RS-
232 PHY. See Figure 6 below for jumper position options. See Figure 4 below for jumper
position options.
RS-232
The TWR-S12G128 applies the MAX3387E, RS-232 physical layer transceiver (PHY) to
enable standard serial communications. A standard 2x5 “Berg” pin-header on 0.1” centers and
an IDC to DB9 cable supports connecting standard serial cables to the target board. Figure 4
below shows the SCI signal connections.
CAUTION:
The user must open CT2 when using PAD9/KWAD9 as an analog input or
as GPIO.
Similarly, CT3 must be opened when using PD1 as GPIO

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Figure 4: Serial Connections
MCU Port Signal
Transceiver
Signal
COM
CONNECTOR
COMMENTS
+5V
J5-1
PS1//TXD0
TXD
J5-3
pull-up
PS0//RXD0
RXD
J5-5
PAD9/KWAD9/AN9
DTR
J5-7
CT2 (NC)
GND
J5-9
PD2
DSR
J5-2
pull-up
PD1
CTS
J5-4
CT3 (NC), pull-up
PAD10/KWAD10/AN10
RTS
J5-6
pull-up
TP2
J5-8
PAD8/KWAD8/AN8
INVALID*
CT4 (NO)
PAD15/KWAD15/AN15
FORCEOFF*
CT5 (NC)
NOTE: For normal RS-232 operation, FORCEOFF* should be actively driven to the high level.
Alternately, open CT5 to allow FORCEOFF* to float high.
COM Connector
A 2x5, 0.1”, standard “Berg” pin-header provides external connections for the SCI port. Figure
5 below shows the COM1 pin-out. The TWR-S12G128 ships with a DB-9 to 2x5 IDC
connector cable to interface the target board to standard serial cables.
Figure 5: COM1 Connector
2, 7
1
2
1, 7
TXD
3
4
CTS
RXD
5
6
RTS
1, 2
7
8
TP2
GND
9
10
NC
COM_EN
The COM_EN option header connects the MCU SCI port to either the SCI PHY or the LIN
PHY. Figure 6 below shows the option jumper configuration for the COM_EN option header.
Figure 6: COM_EN Option Header
2
4
6
Connects target MCU SCI port to LIN PHY to enable LIN bus
communications
1
3
5
COM_EN
2
4
6
Connects target MCU SCI port to RS-232 PHY to enable serial
communications (Default)
1
3
5
COM_EN