README
======

README for NuttX port to the Tiva TM4C123G LaunchPad. The Tiva TM4C123G
LaunchPad Evaluation Board is a low-cost evaluation platform for ARM�
Cortex�-M4F-based microcontrollers from Texas Instruments.

Contents
========

On-Board GPIO Usage
LEDs
Serial Console
USB Device Controller Functions
AT24 Serial EEPROM
I2C Tool
Using OpenOCD and GDB with an FT2232 JTAG emulator
TM4C123G LaunchPad Configuration Options
Configurations

On-Board GPIO Usage
===================

PIN SIGNAL(S) LanchPad Function
--- ---------------------------------------- ---------------------------------------
17 PA0/U0RX DEBUG/VCOM, Virtual COM port receive
18 PA1/U0TX DEBUG/VCOM, Virtual COM port transmit
19 PA2/SSIOCLK GPIO, J2 pin 10
20 PA3/SSIOFSS GPIO, J2 pin 9
21 PA4/SSIORX GPIO, J2 pin 8
22 PA5/SSIOTX GPIO, J1 pin 8
23 PA6/I2CLSCL GPIO, J1 pin 9
24 PA7/I2CLSDA GPIO, J1 pin 10

45 PB0/T2CCP0/U1Rx GPIO, J1 pin 3
46 PB1/T2CCP1/U1Tx GPIO, J1 pin 4
47 PB2/I2C0SCL/T3CCP0 GPIO, J2 pin 2
48 PB3/I2C0SDA/T3CCP1 GPIO, J4 pin 3
58 PB4/AIN10/CAN0Rx/SSI2CLK/T1CCP0 GPIO, J1 pin 7
57 PB5/AIN11/CAN0Tx/SSI2FSS/T1CCP1 GPIO, J1 pin 2
01 PB6/SSI2RX/T0CCP0 Connects to PD0 via resistor, GPIO, J2 pin 7
04 PB7/SSI2TX/T0CCP1 Connects to PD1 via resistor, GPIO, J2 pin 6

52 PC0/SWCLK/T4CCP0/TCK DEBUG/VCOM
51 PC1/SWDIO/T4CCP1/TMS DEBUG/VCOM
50 PC2/T5CCP0/TDI DEBUG/VCOM
49 PC3/SWO/T5CCP1/TDO DEBUG/VCOM
16 PC4/C1-/U1RTS/U1RX/U4RX/WT0CCP0 GPIO, J4 pin 4
15 PC5/C1+/U1CTS/U1TX/U4TX/WT0CCP1 GPIO, J4 pin 5
14 PC6/C0+/U3RX/WT1CCP0 GPIO, J4 pin 6
13 PC7/C0-/U3TX/WT1CCP1 GPIO, J4 pin 7

61 PD0/AIN7/I2C3SCL/SSI1CLK/SSI3CLKWT2CCP0 Connects to PB6 via resistor, GPIO, J3 pin 3
62 PD1/AIN6/I2C3SDA/SSI1Fss/SSI3Fss/WT2CCP1 Connects to PB7 via resistor, GPIO, J3 Pin 4
63 PD2/AIN5/SSI1RX/SSI3RX/WT3CCP0 GPIO, J3 pin 5
64 PD3/AIN4/SSI1TX/SSI3TX/WT3CCP1 GPIO, J3 pin 6
43 PD4/U6RX/USB0DM/WT4CCP0 USB_DM
44 PD5/U6TX/USB0DP/WT4CCP1 USB_DP
53 PD6/U2RX/WT5CCP0 GPIO, J4 pin 8
10 PD7/NMI/U2TX/WT5CCP1 +USB_VBUS, GPIO, J4 pin 9
Used for VBUS detection when
configured as a self-powered USB
Device

09 PE0/AIN3/U7RX GPIO, J2 pin 3
08 PE1/AIN2/U7TX GPIO, J3 pin 7
07 PE2/AIN1 GPIO, J3 pin 8
06 PE3/AIN0 GPIO, J3 pin 9
59 PE4/AIN9/CAN0RX/I2C2SCL/U5RX GPIO, J1 pin 5
60 PE5/AIN8/CAN0TX/I2C2SDA/U5TX GPIO, J1 pin 6

28 PF0/C0O/CAN0RX/NMI/SSI1RX/T0CCP0/U1RTS USR_SW2 (Low when pressed), GPIO, J2 pin 4
29 PF1/C1O/SSI1TX/T0CCP1/TRD1/U1CTS LED_R, GPIO, J3 pin 10
30 PF2/SSI1CLK/T1CCP0/TRD0 LED_B, GPIO, J4 pin 1
31 PF3/CAN0TX/SSI1FSS/T1CCP1/TRCLK LED_G, GPIO, J4 pin 2
05 PF4/T2CCP0 USR_SW1 (Low when pressed), GPIO, J4 pin 10

AT24 Serial EEPROM
==================

AT24 Connections
----------------

A AT24C512 Serial EEPPROM was used for tested I2C. There are no I2C
devices on-board the Launchpad, but an external serial EEPROM module
module was used.

The Serial EEPROM was mounted on an external adaptor board and connected
to the LaunchPad thusly:

- VCC J1 pin 1 3.3V
J3 pin 1 5.0V
- GND J2 pin 1 GND
J3 pin 2 GND
- PB2 J2 pin 2 SCL
- PB3 J4 pin 3 SDA

Configuration Settings
----------------------

The following configuration settings were used:

System Type -> Tiva/Stellaris Peripheral Support
CONFIG_TIVA_I2C0=y : Enable I2C

System Type -> I2C device driver options
TIVA_I2C_FREQUENCY=100000 : Select an I2C frequency

Device Drivers -> I2C Driver Support
CONFIG_I2C=y : Enable I2C support

Device Drivers -> Memory Technology Device (MTD) Support
CONFIG_MTD=y : Enable MTD support
CONFIG_MTD_AT24XX=y : Enable the AT24 driver
CONFIG_AT24XX_SIZE=512 : Specifies the AT 24C512 part
CONFIG_AT24XX_ADDR=0x53 : AT24 I2C address

Application Configuration -> NSH Library
CONFIG_NSH_ARCHINIT=y : NSH board-initialization

File systems
CONFIG_NXFFS=y : Enables the NXFFS file system
CONFIG_NXFFS_PREALLOCATED=y : Required
: Other defaults are probably OK

Board Selection
CONFIG_TM4C123G_LAUNCHPAD_AT24_BLOCKMOUNT=y : Mounts AT24 for NSH
CONFIG_TM4C123G_LAUNCHPAD_AT24_NXFFS=y : Mount the AT24 using NXFFS

You can then format the AT24 EEPROM for a FAT file system and mount the
file system at /mnt/at24 using these NSH commands:

nsh> mkfatfs /dev/mtdblock0
nsh> mount -t vfat /dev/mtdblock0 /mnt/at24

Then you an use the FLASH as a normal FAT file system:

nsh> echo "This is a test" >/mnt/at24/atest.txt
nsh> ls -l /mnt/at24
/mnt/at24:
-rw-rw-rw- 16 atest.txt
nsh> cat /mnt/at24/atest.txt
This is a test

STATUS:
2014-12-12: I was unsuccessful getting my AT24 module to work on the TM4C123G
LaunchPad. I was unable to successuflly communication with the AT24 via
I2C. I did verify I2C using the I2C tool and other I2C devices and I now
belive that my AT24 module is not fully functional.

I2C Tool
========

I2C Tool. NuttX supports an I2C tool at apps/system/i2c that can be used
to peek and poke I2C devices. That tool can be enabled by setting the
following:

System Type -> TIVA Peripheral Support
CONFIG_TIVA_I2C0=y : Enable I2C0
CONFIG_TIVA_I2C1=y : Enable I2C1
CONFIG_TIVA_I2C2=y : Enable I2C2
...

System Type -> I2C device driver options
CONFIG_TIVA_I2C0_FREQUENCY=100000 : Select an I2C0 frequency
CONFIG_TIVA_I2C1_FREQUENCY=100000 : Select an I2C1 frequency
CONFIG_TIVA_I2C2_FREQUENCY=100000 : Select an I2C2 frequency
...

Device Drivers -> I2C Driver Support
CONFIG_I2C=y : Enable I2C support

Application Configuration -> NSH Library
CONFIG_SYSTEM_I2CTOOL=y : Enable the I2C tool
CONFIG_I2CTOOL_MINBUS=0 : I2C0 has the minimum bus number 0
CONFIG_I2CTOOL_MAXBUS=2 : I2C2 has the maximum bus number 2
CONFIG_I2CTOOL_DEFFREQ=100000 : Pick a consistent frequency

The I2C tool has extensive help that can be accessed as follows:

nsh> i2c help
Usage: i2c [arguments]
Where is one of:

Show help : ?
List busses : bus
List devices : dev [OPTIONS]
Read register : get [OPTIONS] []
Show help : help
Write register: set [OPTIONS] []
Verify access : verf [OPTIONS] [] []

Where common "sticky" OPTIONS include:
[-a addr] is the I2C device address (hex). Default: 03 Current: 03
[-b bus] is the I2C bus number (decimal). Default: 0 Current: 0
[-r regaddr] is the I2C device register address (hex). Default: 00 Current: 00
[-w width] is the data width (8 or 16 decimal). Default: 8 Current: 8
[-s|n], send/don't send start between command and data. Default: -n Current: -n
[-i|j], Auto increment|don't increment regaddr on repititions. Default: NO Current: NO
[-f freq] I2C frequency. Default: 100000 Current: 100000

NOTES:
o Arguments are "sticky". For example, once the I2C address is
specified, that address will be re-used until it is changed.

WARNING:
o The I2C dev command may have bad side effects on your I2C devices.
Use only at your own risk.

As an example, the I2C dev command can be used to list all devices
responding on I2C0 (the default) like this:

nsh> i2c dev 0x03 0x77
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- 1a -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- 39 -- -- -- 3d -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: 60 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
nsh>

NOTE: This is output from a different board and shows I2C
devices responding at addresses 0x1a, 0x39, 0x3d, and 0x60.

Using OpenOCD and GDB with an FT2232 JTAG emulator
==================================================

Building OpenOCD under Cygwin:

Refer to configs/olimex-lpc1766stk/README.txt

Installing OpenOCD in Linux:

sudo apt-get install openocd

As of this writing, there is no support for the tm4c123g in the package
above. You will have to build openocd from its source (as of this writing
the latest commit was b9b4bd1a6410ff1b2885d9c2abe16a4ae7cb885f):

git clone http://git.code.sf.net/p/openocd/code openocd
cd openocd

Then, add the patches provided by http://openocd.zylin.com/922:

git fetch http://openocd.zylin.com/openocd refs/changes/22/922/14 && git checkout FETCH_HEAD
./bootstrap
./configure --enable-maintainer-mode --enable-ti-icdi
make
sudo make install

For additional help, see http://processors.wiki.ti.com/index.php/Tiva_Launchpad_with_OpenOCD_and_Linux

Helper Scripts.

I have been using the on-board In-Circuit Debug Interface (ICDI) interface.
OpenOCD requires a configuration file. I keep the one I used last here:

configs/tm4c123g-launchpad/tools/tm4c123g-launchpad.cfg

However, the "correct" configuration script to use with OpenOCD may
change as the features of OpenOCD evolve. So you should at least
compare that tm4c123g-launchpad.cfg file with configuration files in
/usr/share/openocd/scripts. As of this writing, the configuration
files of interest were:

/usr/local/share/openocd/scripts/board/ek-tm4c123gxl.cfg
/usr/local/share/openocd/scripts/interface/ti-icdi.cfg
/usr/local/share/openocd/scripts/target/stellaris_icdi.cfg

There is also a script on the tools/ directory that I use to start
the OpenOCD daemon on my system called oocd.sh. That script will
probably require some modifications to work in another environment:

- Possibly the value of OPENOCD_PATH and TARGET_PATH
- It assumes that the correct script to use is the one at
configs/tm4c123g-launchpad/tools/tm4c123g-launchpad.cfg

Starting OpenOCD

If you are in the top-level NuttX build directlory then you should
be able to start the OpenOCD daemon like:

oocd.sh $PWD

The relative path to the oocd.sh script is configs/tm4c123g-launchpad/tools.
You may want to add that path to you PATH variable.

Note that OpenOCD needs to be run with administrator privileges in
some environments (sudo).

Connecting GDB

Once the OpenOCD daemon has been started, you can connect to it via
GDB using the following GDB command:

arm-nuttx-elf-gdb
(gdb) target remote localhost:3333

NOTE: The name of your GDB program may differ. For example, with the
CodeSourcery toolchain, the ARM GDB would be called arm-none-eabi-gdb.

After starting GDB, you can load the NuttX ELF file:

(gdb) symbol-file nuttx
(gdb) monitor reset
(gdb) monitor halt
(gdb) load nuttx

NOTES:
1. Loading the symbol-file is only useful if you have built NuttX to
include debug symbols (by setting CONFIG_DEBUG_SYMBOLS=y in the
.config file).
2. The MCU must be halted prior to loading code using 'mon reset'
as described below.

OpenOCD will support several special 'monitor' commands. These
GDB commands will send comments to the OpenOCD monitor. Here
are a couple that you will need to use:

(gdb) monitor reset
(gdb) monitor halt

NOTES:
1. The MCU must be halted using 'mon halt' prior to loading code.
2. Reset will restart the processor after loading code.
3. The 'monitor' command can be abbreviated as just 'mon'.

LEDs
====
The TM4C123G has a single RGB LED. If CONFIG_ARCH_LEDS is defined, then
support for the LaunchPad LEDs will be included in the build. See:

- configs/tm4c123g-launchpad/include/board.h - Defines LED constants, types and
prototypes the LED interface functions.

- configs/tm4c123g-launchpad/src/tm4c123g-launchpad.h - GPIO settings for the LEDs.

- configs/tm4c123g-launchpad/src/up_leds.c - LED control logic.

OFF:
- OFF means that the OS is still initializing. Initialization is very fast so
if you see this at all, it probably means that the system is hanging up
somewhere in the initialization phases.

GREEN or GREEN-ish
- This means that the OS completed initialization.

Bluish:
- Whenever and interrupt or signal handler is entered, the BLUE LED is
illuminated and extinguished when the interrupt or signal handler exits.
This will add a BLUE-ish tinge to the LED.

Redish:
- If a recovered assertion occurs, the RED component will be illuminated
briefly while the assertion is handled. You will probably never see this.

Flashing RED:
- In the event of a fatal crash, the BLUE and GREEN components will be
extinguished and the RED component will FLASH at a 2Hz rate.

Serial Console
==============

By default, all configurations use UART0 which connects to the USB VCOM
on the DEBUG port on the TM4C123G LaunchPad:

UART0 RX - PA.0
UART0 TX - PA.1

However, if you use an external RS232 driver, then other options are
available. UART1 has option pin settings and flow control capabilities
that are not available with the other UARTS::

UART1 RX - PB.0 or PC.4 (Need disambiguation in board.h)
UART1 TX - PB.1 or PC.5 (" " " " "" " ")

UART1_RTS - PF.0 or PC.4
UART1_CTS - PF.1 or PC.5

NOTE: board.h currently selects PB.0, PB.1, PF.0 and PF.1 for UART1, but
that can be changed by editting board.h

UART2-5, 7 are also available, UART2 is not recommended because it shares
some pin usage with USB device mode. UART6 is not available because its
only RX/TX pin options are dedicated to USB support.

UART2 RX - PD.6
UART2 TX - PD.7 (Also used for USB VBUS detection)

UART3 RX - PC.6
UART3 TX - PC.7

UART4 RX - PC.4
UART4 TX - PC.5

UART5 RX - PE.4
UART5 TX - PE.5

UART6 RX - PD.4, Not available. Dedicated for USB_DM
UART6 TX - PD.5, Not available. Dedicated for USB_DP

UART7 RX - PE.0
UART7 TX - PE.1

USB Device Controller Functions
===============================

Device Overview

An FT2232 device from Future Technology Devices International Ltd manages
USB-to-serial conversion. The FT2232 is factory configured by Luminary
Micro to implement a JTAG/SWD port (synchronous serial) on channel A and
a Virtual COM Port (VCP) on channel B. This feature allows two simultaneous
communications links between the host computer and the target device using
a single USB cable. Separate Windows drivers for each function are provided
on the Documentation and Software CD.

Debugging with JTAG/SWD

The FT2232 USB device performs JTAG/SWD serial operations under the control
of the debugger or the Luminary Flash Programmer. It also operate as an
In-Circuit Debugger Interface (ICDI), allowing debugging of any external
target board. Debugging modes:

MODE DEBUG FUNCTION USE SELECTED BY
1 Internal ICDI Debug on-board TM4C123G Default Mode
microcontroller over USB
interface.
2 ICDI out to JTAG/SWD The EVB is used as a USB Connecting to an external
header to SWD/JTAG interface to target and starting debug
an external target. software. The red Debug Out
LED will be ON.
3 In from JTAG/SWD For users who prefer an Connecting an external
header external debug interface debugger to the JTAG/SWD
(ULINK, JLINK, etc.) with header.
the EVB.

Virtual COM Port

The Virtual COM Port (VCP) allows Windows applications (such as HyperTerminal)
to communicate with UART0 on the TM4C123G over USB. Once the FT2232 VCP
driver is installed, Windows assigns a COM port number to the VCP channel.

TM4C123G LaunchPad Configuration Options
=======================================================

CONFIG_ARCH - Identifies the arch/ subdirectory. This should
be set to:

CONFIG_ARCH=arm

CONFIG_ARCH_family - For use in C code:

CONFIG_ARCH_ARM=y

CONFIG_ARCH_architecture - For use in C code:

CONFIG_ARCH_CORTEXM4=y

CONFIG_ARCH_CHIP - Identifies the arch/*/chip subdirectory

CONFIG_ARCH_CHIP="tiva"

CONFIG_ARCH_CHIP_name - For use in C code to identify the exact
chip:

CONFIG_ARCH_CHIP_TM4C123GH6PMI

CONFIG_ARCH_BOARD - Identifies the configs subdirectory and
hence, the board that supports the particular chip or SoC.

CONFIG_ARCH_BOARD=tm4c123g-launchpad (for the TM4C123G LaunchPad)

CONFIG_ARCH_BOARD_name - For use in C code

CONFIG_ARCH_BOARD_TM4C123G_LAUNCHPAD

CONFIG_ARCH_LOOPSPERMSEC - Must be calibrated for correct operation
of delay loops

CONFIG_ENDIAN_BIG - define if big endian (default is little
endian)

CONFIG_RAM_SIZE - Describes the installed DRAM (SRAM in this case):

CONFIG_RAM_SIZE=0x00008000 (32Kb)

CONFIG_RAM_START - The start address of installed DRAM

CONFIG_RAM_START=0x20000000

CONFIG_ARCH_LEDS - Use LEDs to show state. Unique to boards that
have LEDs

CONFIG_ARCH_INTERRUPTSTACK - This architecture supports an interrupt
stack. If defined, this symbol is the size of the interrupt
stack in bytes. If not defined, the user task stacks will be
used during interrupt handling.

CONFIG_ARCH_STACKDUMP - Do stack dumps after assertions

CONFIG_ARCH_LEDS - Use LEDs to show state. Unique to board architecture.

There are configurations for disabling support for interrupts GPIO ports.
Only GPIOP and GPIOQ pins can be used as interrupting sources on the
TM4C129x. Additional interrupt support can be disabled if desired to
reduce memory footprint.

CONFIG_TIVA_GPIOP_IRQS=y
CONFIG_TIVA_GPIOQ_IRQS=y

TM4C123G specific device driver settings

CONFIG_UARTn_SERIAL_CONSOLE - selects the UARTn for the
console and ttys0 (default is the UART0).
CONFIG_UARTn_RXBUFSIZE - Characters are buffered as received.
This specific the size of the receive buffer
CONFIG_UARTn_TXBUFSIZE - Characters are buffered before
being sent. This specific the size of the transmit buffer
CONFIG_UARTn_BAUD - The configure BAUD of the UART. Must be
CONFIG_UARTn_BITS - The number of bits. Must be either 7 or 8.
CONFIG_UARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity
CONFIG_UARTn_2STOP - Two stop bits

CONFIG_TIVA_SSI0 - Select to enable support for SSI0
CONFIG_TIVA_SSI1 - Select to enable support for SSI1
CONFIG_SSI_POLLWAIT - Select to disable interrupt driven SSI support.
Poll-waiting is recommended if the interrupt rate would be to
high in the interrupt driven case.
CONFIG_SSI_TXLIMIT - Write this many words to the Tx FIFO before
emptying the Rx FIFO. If the SPI frequency is high and this
value is large, then larger values of this setting may cause
Rx FIFO overrun errors. Default: half of the Tx FIFO size (4).

CONFIG_TIVA_ETHERNET - This must be set (along with CONFIG_NET)
to build the Tiva Ethernet driver
CONFIG_TIVA_ETHLEDS - Enable to use Ethernet LEDs on the board.
CONFIG_TIVA_BOARDMAC - If the board-specific logic can provide
a MAC address (via tiva_ethernetmac()), then this should be selected.
CONFIG_TIVA_ETHHDUPLEX - Set to force half duplex operation
CONFIG_TIVA_ETHNOAUTOCRC - Set to suppress auto-CRC generation
CONFIG_TIVA_ETHNOPAD - Set to suppress Tx padding
CONFIG_TIVA_MULTICAST - Set to enable multicast frames
CONFIG_TIVA_PROMISCUOUS - Set to enable promiscuous mode
CONFIG_TIVA_BADCRC - Set to enable bad CRC rejection.
CONFIG_TIVA_DUMPPACKET - Dump each packet received/sent to the console.

Configurations
==============

Each TM4C123G LaunchPad configuration is maintained in a
sub-directory and can be selected as follow:

tools/configure.sh tm4c123g-launchpad/

Where is one of the following:

nsh:
---
Configures the NuttShell (nsh) located at apps/examples/nsh. The
configuration enables the serial VCOM interfaces on UART0. Support for
builtin applications is enabled, but in the base configuration no
builtin applications are selected.

NOTES:

1. This configuration uses the mconf-based configuration tool. To
change this configuration using that tool, you should:

a. Build and install the kconfig-mconf tool. See nuttx/README.txt
see additional README.txt files in the NuttX tools repository.

b. Execute 'make menuconfig' in nuttx/ in order to start the
reconfiguration process.

2. By default, this configuration uses the CodeSourcery toolchain
for Windows and builds under Cygwin (or probably MSYS). That
can easily be reconfigured, of course.

CONFIG_HOST_LINUX=y : Linux (Cygwin under Windows okay too).
CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : Buildroot (arm-nuttx-elf-gcc)
CONFIG_RAW_BINARY=y : Output formats: ELF and raw binary