README
This README file discusses the port of NuttX to the Silicon Labs EFM32™ Giant Gecko Starter Kit (EFM32GG-STK3400). The Giant Gecko Starter Kit features:
• EFM32GG990F1024 MCU with 1 MB flash and 128 kB RAM
• 32.768 kHz crystal (LXFO)
• 48 MHz crystal (HXFO)
• 32 MB NAND flash
• Advanced Energy Monitoring
• Touch slider
• 8x20 LCD
• 2 user LEDs
• 2 user buttons
• USB interface for Host/Device/OTG
• Ambient light sensor and inductive-capacitive metal sensor
• EFM32 OPAMP footprint
• 20 pin expansion header
• Breakout pads for easy access to I/O pins
• Power sources (USB and CR2032 battery)
• Backup Capacitor for RTC mode
• Integrated Segger J-Link USB debugger/emulator
STATUS
2014-11-02: Completed the basic NSH configuration for the EFM32 Giant Gecko Starter Kit. 2014-11-12: The basic NSH configuration is functional with a serial console on LEUART0. 2014-11-14: LEUART0 BAUD increased from 2400 to 9600. Calibrated delay loop. 2014-11-18: Added basic drivers for USB device and host. The initial port is a simple leverage from the STM32 which appears to use the same IP. The current state is just the STM32 USB drivers with the appropriate. The USB drivers still lack EFM32 initialization logic and are, of course, completely untested.
LEDs and Buttons
LEDs
The EFM32 Giant Gecko Start Kit has two yellow LEDs marked LED0 and LED1. These LEDs are controlled by GPIO pins on the EFM32. The LEDs are connected to pins PE2 and PE3 in an active high configuration:
EFM32 PIN BOARD SIGNALS
E2/BCK_VOUT/EBI_A09 #0/ MCU_PE2 UIF_LED0 TIM3_CC2 #1/U1_TX #3/ACMP0_O #1 E3/BCK_STAT/EBI_A10 #0/U1_RX #3/ MCU_PE3 UIF_LED1 ACMP1_O #1 -------------------------------------
All LEDs are grounded and so are illuminated by outputting a high value to the LED.
These LEDs are not used by the board port unless CONFIG_ARCH_LEDS is defined. In that case, the usage by the board port is defined in include/board.h and src/efm32_autoleds.c. The LEDs are used to encode OS-related events as follows:
These LEDs are not used by the board port unless CONFIG_ARCH_LEDS is defined. In that case, the usage by the board port is defined in include/board.h and src/up_leds.c. The LEDs are used to encode OS-related events as follows:
SYMBOL Meaning LED state
LED0 LED1
------------------- ----------------------- -------- --------
LED_STARTED NuttX has been started OFF OFF
LED_HEAPALLOCATE Heap has been allocated OFF OFF
LED_IRQSENABLED Interrupts enabled OFF OFF
LED_STACKCREATED Idle stack created ON OFF
LED_INIRQ In an interrupt No change
LED_SIGNAL In a signal handler No change
LED_ASSERTION An assertion failed No change
LED_PANIC The system has crashed OFF Blinking
LED_IDLE STM32 is is sleep mode Not used
Thus if LED0 statically on, NuttX has successfully booted and is, apparently, running normally. If LED1 is flashing at approximately 2Hz, then a fatal error has been detected and the system has halted.
Buttons
The EFM32 Giant Gecko Start Kit has two buttons marked PB0 and PB1. They are connected to the EFM32, and are debounced by RC filters with a time constant of 1ms. The buttons are connected to pins PB9 and PB10:
------------------------------------- --------------------
EFM32 PIN BOARD SIGNALS
------------------------------------- --------------------
B9/EBI_A03/U1_TX #2 MCU_PB9 UIF_PB0
B10/EBI_A04/U1_RX #2 MCU_PB10 UIF_PB1
------------------------------------- --------------------
Buttons are connected to ground so they will read low when closed.
Serial Console
Default Serial Console
LEUART0 is configured as the default serial console at 9600 8N1 on pins PD5 and PD4.
---------- ---- ----------- -----------
SIGNAL PGIO EXP Header Test Point
---------- ---- ----------- -----------
LEUART0_TX PD4 Pin 12 TPJ122
LEUART0_RX PD5 Pin 14 TPJ123
---------- ---- ----------- -----------
It should also be possible to use UART0 is configured at 115200 8N1 on pins PE0 and PE1.
Communication through the Board Controller
The kit contains a board controller that is responsible for performing various board level tasks, such as handling the debugger and the Advanced Energy Monitor. An interface is provided between the EFM32 and the board controller in the form of a UART connection. The connection is enabled by setting the EFM_BC_EN (PF7) line high, and using the lines EFM_BC_TX (PE0) and EFM_BC_RX (PE1) for communicating.
USING THE J-LINK GDB SERVER
Star the J-Link GDB server. You should see the start-up configuration window. SelectL
a. Target device = EFM32GG990F1024 b. Select Target interface = SWD
Press OK. The GDB server should start and the last message in the Log output should be "Waiting for GDB connection".
In a terminal window, start GDB:
arm-none-eabi-gdb
Connect to the J-Link GDB server:
<!-- --> (gdb) target remote localhost:2331
- Load and run nuttx
<!-- --> (gdb) mon halt
(gdb) load nuttx
(gdb) mon reset go
I had to tinker with the setup a few times repeating the same steps above before things finally began to work. Don't know why.
To debug code already burned into FLASH:
Start the GDB server as above.
In a terminal window, start GDB:
arm-none-eabi-gdb
Connect to the J-Link GDB serer:
<!-- --> (gdb) target remote local host
- Load the nuttx symbol file, reset, and debug
<!-- --> (gdb) mon halt
(gdb) file nuttx
(gdb) mon reset
(gdb) s
...
Configurations
Each EFM32 Giant Gecko Starter Kit configuration is maintained in a sub- directory and can be selected as follow:
tools/configure.sh efm32gg-stk3700:<subdir>
If this is a Windows native build, then configure.bat should be used instead of configure.sh:
configure.bat efm32gg-stk3700\<subdir>
Where <subdir> is one of the following:
nsh:
Configures the NuttShell (nsh) located at apps/examples/nsh. The Configuration enables the serial interfaces on LEUART0 at 9600 8N1.
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 ARM EABI toolchain
for Windows and builds under Cygwin (or probably MSYS). That
can easily be reconfigured, of course.
CONFIG_HOST_WINDOWS=y : Builds under Windows
CONFIG_WINDOWS_CYGWIN=y : Using Cygwin
CONFIG_ARM_TOOLCHAIN_GNU_EABI=y : GNU EABI toolchain for Windows