README
======
This README discusses issues unique to NuttX configurations for the
STMicro STM32L-Discovery development board. The STM32L-Discovery board
is based on the STM32L152RBT6 MCU (128KB FLASH and 16KB of SRAM).
The STM32L-Discovery and 32L152CDISCOVERY kits are functionally
equivalent. The difference is the internal Flash memory size (STM32L152RBT6
with 128 Kbytes or STM32L152RCT6 with 256 Kbytes).
Both boards feature:
- An ST-LINK/V2 embedded debug tool interface,
- LCD (24 segments, 4 commons),
- LEDs,
- Pushbuttons,
- A linear touch sensor, and
- Four touchkeys.
Contents
========
- Status
- GPIO Pin Usage
- LEDs
- Serial Console
- Debugging
- STM32L-Discovery-specific Configuration Options
- Configurations
Status
======
The basic port is complete. A NuttShell (NSH) configuration exists for the
STM32L-Discovery board. A driver has been developed for the segment LCD on
board the STM32L-Discovery. In the NSH configuration description below,
there is information about how the basic NSH extension can be extended to
use apps/examples/slcd to exercise the segment LCD.
* The following subsystem have header files, drivers and have been
exercised: PWR, RCC, GPIO, SYSCFG, LCD, USART.
* The following subsystems have header files and ported drivers, but are
untested: DMA
* The following subsystems have counterparts with other STM32 parts, but
have not been ported or verified: ADC, DAC, TIM2-15, TIM9-11, RTC,
IWDG, WWDG, I2C, SPI, DBG. These may be close to functional depending
upon how close the IP is on the STM32L15X.
This might include also USB, FSMC, and SDIO.
* The following subsystems are unique to the STM32L and have not been
developed: COMP, TSIO, RI, OPAMP
* The STM32L15X does support USB, however, USB is not available on the
STM32L-Discovery board.
* These subsystems are available on other STM32L15x/16x parts, but not on
the part used in the STM32L-Discovery board: CRC, AES, FSMC, SDIO
GPIO Pin Usage
==============
----- --------------------- -------------------------------- ----------------
GPIO ALTERNATE FUNCTION BOARD FUNCTION P1/P2
----- --------------------- -------------------------------- ----------------
PA0 WKUP1/USART2_CTS/ Push button (PA0), WAKE UP (Iuu) P1, pin 15
ADC_IN0/TIM2_CH1_ETR
/COMP1_INP
PA1 USART2_RTS/ADC_IN1/ LCD SEG0 P1, pin 16
TIM2_CH2/LCD_SEG0/
COMP1_INP
PA2 USART2_TX/ADC_IN2/ LCD SEG1 P1, pin 17
TIM2_CH3/TIM9_CH1/
LCD_SEG1/COMP1_INP
PA3 USART2_RX/ADC_IN3/ LCD SEG2 P1, pin 18
TIM2_CH4/TIM9_CH2/
LCD_SEG2/COMP1_INP
PA4 SPI1_NSS/USART2_CK/ Measurement (Iuu) P1, pin 19
ADC_IN4/DAC_OUT1/
COMP1_INP
PA5 SPI1_SCK/ADC_IN5/ --- P1, pin 20
DAC_OUT2/
TIM2_CH1_ETR/COMP1_
INP
PA6 SPI1_MISO/ADC_IN6/ Linear Touch Sensor (PA6) ---
TIM3_CH1/TIM1_BKIN/
LCD_SEG3/TIM10_CH1/
COMP1_INP
PA7 SPI1_MOSI/ADC_IN7/ Linear Touch Sensor (PA7) ---
TIM3_CH2/TIM1_CH1N
/LCD_SEG4/TIM11_CH1/
PA8 USART1_CK/MCO/ LCD glass COM0 P2, pin 23
LCD_COM0
PA9 USART1_TX/LCD_COM1 LCD glass COM1 P2, pin 22
PA10 USART1_RX/LCD_COM2 LCD glass COM2 P2, pin 21
PA11 USART1_CTS/USBDM/ --- P2, pin 20
SPI1_MISO
PA12 USART1_RTS/USBDP/ --- P2, pin 19
SPI1_MOSI
JTDI TIM2_CH1_ETR/PA15/ LCD_SEG12 P2, pin 16
SPI1_NSS/LCD_SEG17
----- --------------------- -------------------------------- ----------------
PB0 ADC_IN8/TIM3_CH3/ Linear Touch Sensor (PB0) ---
LCD_SEG5/COMP1_INP/
VREF_OUT
PB1 ADC_IN9/TIM3_CH4/ Linear Touch Sensor (PB1) ---
LCD_SEG6/COMP1_INP/
VREF_OUT
PB2/ --- --- P1, pin 21
BOOT1
JTDO TIM2_CH2/PB3/TRACES LCD_SEG3, SWO P2, pin 11
WO/SPI1_SCK/COMP2_I
NM/LCD_SEG7
JNTRST TIM3_CH1/PB4/SPI1_MIS SEG4 P2, pin 10
O/COMP2_INP/LCD_SEG8
PB5 I2C1_SMBAl/TIM3_CH2/ LCD SEG5 P2, pin 9
SPI1_MOSI/COMP2_INP/
LCD_SEG9
PB6 I2C1_SCL/TIM4_CH1/ LED Blue P2, pin 8
USART1_TX/LCD_SEG8
PB7 I2C1_SDA/TIM4_CH2/ LED Green P2, pin 7
USART1_RX/PVD_IN
PB8 TIM4_CH3/I2C1_SCL/ LCD SEG13 P2, pin 4
LCD_SEG16/TIM10_CH1
PB9 TIM4_CH4/I2C1_SDA/ LCD glass COM3 P2, pin 3
LCD_COM3/TIM11_CH1
PB10 I2C2_SCL/USART3_TX/ LCD SEG6 P1, pin 22
TIM2_CH3/LCD_SEG10
PB11 I2C2_SDA/USART3_RX/ LCD SEG7 P1, pin 23
TIM2_CH4/LCD_SEG11
PB12 SPI2_NSS/I2C2_SMBA/ LCD SEG8 P1, pin 24
USART3_CK/LCD_SEG12
2/ADC_IN18/COMP1_INP
/ TIM10_CH1
PB13 SPI2_SCK/USART3_CTS/ LCD SEG9 P1, pin 25
LCD_SEG13/ADC_IN19/
COMP1_INP/TIM9_CH1
PB14 SPI2_MISO/USART3_RT LCD SEG10 P1, pin 26
S/LCD_SEG14/ADC_IN20
/ COMP1_INP/TIM9_CH2
PB15 SPI2_MOSI/TIM1_CH3N/ LCD SEG11 P1, pin 27
LCD_SEG15/ADC_IN21/
COMP1_INP/TIM11_CH1/
RTC_50_60Hz
----- --------------------- -------------------------------- ----------------
PC0 ADC_IN10/LCD_SEG18/ LCD SEG14 P1, pin 11
COMP1_INP
PC1 ADC_IN11/LCD_SEG19/ LCD SEG15 P1, pin 12
COMP1_INP
PC2 ADC_IN12/LCD_SEG20/ LCD SEG16 P1, pin 13
COMP1_INP
PC3 ADC_IN13/LCD_SEG21/ LCD SEG17 P1, pin 14
COMP1_INP
PC4 ADC_IN14/LCD_SEG22/ Linear Touch Sensor (PC4) ---
COMP1_INP
PC5 ADC_IN15/LCD_SEG23/ Linear Touch Sensor (PC5) ---
COMP1_INP
PC6 TIM3_CH1/LCD_SEG24 LCD SEG18 P2, pin 27
PC7 TIM3_CH2/LCD_SEG25 LCD SEG19 P2, pin 26
PC8 TIM3_CH3/LCD_SEG26 LCD SEG20 P2, pin 25
PC9 TIM3_CH4/LCD_SEG27 LCD SEG21 P2, pin 24
PC10 USART3_TX/LCD_SEG28 LCD SEG22 P2, pin 15
/LCD_SEG40/LCD_COM4
PC11 USART3_RX/LCD_SEG2 LCD SEG23 P2, pin 14
9/LCD_SEG41/
LCD_COM5
PC12 USART3_CK/LCD_SEG3 --- P2, pin 13
0/LCD_SEG42/
LCD_COM6
PC13 RTC_AF1/WKUP2 2 CNT_ IDD CNT_EN P1, pin 4
EN 4
PC14 OSC32_IN 3 OSC32_IN OSC32_IN P1, pin 5
PC15 OSC32_OUT 4 OSC32_OUT OSC32_OUT P1, pin 6
----- --------------------- -------------------------------- ----------------
PD2 TIM3_ETR/LCD_SEG31/ --- P2, pin 12
LCD_SEG43/LCD_COM7
----- --------------------- -------------------------------- ----------------
LEDs
====
The STM32L-Discovery board has four LEDs. Two of these are controlled by
logic on the board and are not available for software control:
LD1 COM: LD2 default status is red. LD2 turns to green to indicate
that communications are in progress between the PC and the
ST-LINK/V2.
LD2 PWR: Red LED indicates that the board is powered.
And two LEDs can be controlled by software:
User LD3: Green LED is a user LED connected to the I/O PB7 of the
STM32L152 MCU.
User LD4: Blue LED is a user LED connected to the I/O PB6 of the
STM32L152 MCU.
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/stm32_autoleds.c. The LEDs are used to encode
OS-related events as follows:
SYMBOL Meaning LED state
LED3 LED4
------------------- ----------------------- -------- --------
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
Serial Console
==============
The STM32L-Discovery has no on-board RS-232 driver. Further, there are no
USART pins that do not conflict with the on board resources, in particular,
the LCD: Most USART pins are available if the LCD is enabled; USART2 may
be used if either the LCD or the on-board LEDs are disabled.
PA9 USART1_TX LCD glass COM1 P2, pin 22
PA10 USART1_RX LCD glass COM2 P2, pin 21
PB6 USART1_TX LED Blue P2, pin 8
PB7 USART1_RX LED Green P2, pin 7
PA2 USART2_TX LCD SEG1 P1, pin 17
PA3 USART2_RX LCD SEG2 P1, pin 18
PB10 USART3_TX LCD SEG6 P1, pin 22
PB11 USART3_RX LCD SEG7 P1, pin 23
PC10 USART3_TX LCD SEG22 P2, pin 15
PC11 USART3_RX LCD SEG23 P2, pin 14
NOTES:
- GND and (external) 5V are available on both P1 and P2. Note: These
signals may be at lower voltage levels and, hence, may not properly
drive an external RS-232 transceiver.
- The crystal X3 is not installed on the STM32L3-Discovery. As a result,
the HSE clock is not available and the less accurate HSI must be used.
This may limit the accuracy of the computed baud, especially at higher
BAUD. The HSI is supposedly calibrated in the factory to within 1% at
room temperatures so perhaps this not a issue.
- According to the STM32L-Discovery User Manual, the LCD should be removed
from its socket if you use any of the LCD pins for any other purpose.
I have had no problems using the USART1 with PA9 and PA10 with a 3.3-5V
RS-232 transceiver module at 57600 baud. I have not tried higher baud
rates.
- There is no support for a USB serial connector on the STM32L-Discovery
board. The STM32L152 does support USB, but the USB pins are "free I/O"
on the board and no USB connector is provided. So the use of a USB
console is not option. If you need console output, you will need to
disable either LCD (and use any USART) or the LEDs (and use USART1)
Debugging
=========
STM32 ST-LINK Utility
---------------------
For simply writing to FLASH, I use the STM32 ST-LINK Utility. At least
version 2.4.0 is required (older versions do not recognize the STM32 F3
device). This utility is available from free from the STMicro website.
Debugging
---------
If you are going to use a debugger, you should make sure that the following
settings are selection in your configuration file:
CONFIG_DEBUG_SYMBOLS=y : Enable debug symbols in the build
CONFIG_ARMV7M_USEBASEPRI=y : Use the BASEPRI register to disable interrupts
OpenOCD
-------
I am told that OpenOCD will work with the ST-Link, but I have never tried
it.
https://github.com/texane/stlink
--------------------------------
This is an open source server for the ST-Link that I have never used.
STM32L-Discovery-specific 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=stm32
CONFIG_ARCH_CHIP_name - For use in C code to identify the exact
chip:
CONFIG_ARCH_CHIP_STM32L152RB=y
CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG - Enables special STM32 clock
configuration features.
CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG=n
CONFIG_ARCH_BOARD - Identifies the boards/ subdirectory and
hence, the board that supports the particular chip or SoC.
CONFIG_ARCH_BOARD=stm32fldiscovery (for the STM32L-Discovery development board)
CONFIG_ARCH_BOARD_name - For use in C code
CONFIG_ARCH_BOARD_STM32FLDISCOVERY=y
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=16384 (16Kb)
CONFIG_RAM_START - The start address of installed DRAM
CONFIG_RAM_START=0x20000000
CONFIG_STM32_CCMEXCLUDE - Exclude CCM SRAM from the HEAP
CONFIG_ARCH_FPU - The STM32L-Discovery does not support a floating point unit (FPU)
CONFIG_ARCH_FPU=n
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.
Individual subsystems can be enabled:
AHB
----
(GPIOs are always enabled)
CONFIG_STM32_FLITF
CONFIG_STM32_DMA1
CONFIG_STM32_DMA2
APB2
----
CONFIG_STM32_SYSCFG
CONFIG_STM32_TIM9
CONFIG_STM32_TIM10
CONFIG_STM32_TIM11
CONFIG_STM32_ADC1
CONFIG_STM32_SPI1
CONFIG_STM32_USART1
APB1
----
CONFIG_STM32_TIM2
CONFIG_STM32_TIM3
CONFIG_STM32_TIM4
CONFIG_STM32_TIM5
CONFIG_STM32_TIM6
CONFIG_STM32_TIM7
CONFIG_STM32_LCD
CONFIG_STM32_WWDG
CONFIG_STM32_IWDG
CONFIG_STM32_SPI2
CONFIG_STM32_SPI3
CONFIG_STM32_USART2
CONFIG_STM32_USART3
CONFIG_STM32_I2C1
CONFIG_STM32_I2C2
CONFIG_STM32_USB
CONFIG_STM32_PWR -- Required for RTC
CONFIG_STM32_DAC1
CONFIG_STM32_COMP
Timer devices may be used for different purposes. One special purpose is
to generate modulated outputs for such things as motor control. If CONFIG_STM32_TIMn
is defined (as above) then the following may also be defined to indicate that
the timer is intended to be used for pulsed output modulation, ADC conversion,
or DAC conversion. Note that ADC/DAC require two definition: Not only do you have
to assign the timer (n) for used by the ADC or DAC, but then you also have to
configure which ADC or DAC (m) it is assigned to.
CONFIG_STM32_TIMn_PWM Reserve timer n for use by PWM, n=1,..,14
CONFIG_STM32_TIMn_ADC Reserve timer n for use by ADC, n=1,..,14
CONFIG_STM32_TIMn_ADCm Reserve timer n to trigger ADCm, n=1,..,14, m=1,..,3
CONFIG_STM32_TIMn_DAC Reserve timer n for use by DAC, n=1,..,14
CONFIG_STM32_TIMn_DACm Reserve timer n to trigger DACm, n=1,..,14, m=1,..,2
For each timer that is enabled for PWM usage, we need the following additional
configuration settings:
CONFIG_STM32_TIMx_CHANNEL - Specifies the timer output channel {1,..,4}
NOTE: The STM32 timers are each capable of generating different signals on
each of the four channels with different duty cycles. That capability is
not supported by this driver: Only one output channel per timer.
JTAG Enable settings (by default only SW-DP is enabled):
CONFIG_STM32_JTAG_FULL_ENABLE - Enables full SWJ (JTAG-DP + SW-DP)
CONFIG_STM32_JTAG_NOJNTRST_ENABLE - Enables full SWJ (JTAG-DP + SW-DP)
but without JNTRST.
CONFIG_STM32_JTAG_SW_ENABLE - Set JTAG-DP disabled and SW-DP enabled
STM32L-Discovery specific device driver settings
CONFIG_U[S]ARTn_SERIAL_CONSOLE - selects the USARTn (n=1,2,3) or UART
m (m=4,5) for the console and ttys0 (default is the USART1).
CONFIG_U[S]ARTn_RXBUFSIZE - Characters are buffered as received.
This specific the size of the receive buffer
CONFIG_U[S]ARTn_TXBUFSIZE - Characters are buffered before
being sent. This specific the size of the transmit buffer
CONFIG_U[S]ARTn_BAUD - The configure BAUD of the UART. Must be
CONFIG_U[S]ARTn_BITS - The number of bits. Must be either 7 or 8.
CONFIG_U[S]ARTn_PARTIY - 0=no parity, 1=odd parity, 2=even parity
CONFIG_U[S]ARTn_2STOP - Two stop bits
STM32L-Discovery CAN Configuration
CONFIG_CAN - Enables CAN support (one or both of CONFIG_STM32_CAN1 or
CONFIG_STM32_CAN2 must also be defined)
CONFIG_CAN_EXTID - Enables support for the 29-bit extended ID. Default
Standard 11-bit IDs.
CONFIG_CAN_FIFOSIZE - The size of the circular buffer of CAN messages.
Default: 8
CONFIG_CAN_NPENDINGRTR - The size of the list of pending RTR requests.
Default: 4
CONFIG_CAN_LOOPBACK - A CAN driver may or may not support a loopback
mode for testing. The STM32 CAN driver does support loopback mode.
CONFIG_STM32_CAN1_BAUD - CAN1 BAUD rate. Required if CONFIG_STM32_CAN1
is defined.
CONFIG_STM32_CAN2_BAUD - CAN1 BAUD rate. Required if CONFIG_STM32_CAN2
is defined.
CONFIG_STM32_CAN_TSEG1 - The number of CAN time quanta in segment 1.
Default: 6
CONFIG_STM32_CAN_TSEG2 - the number of CAN time quanta in segment 2.
Default: 7
CONFIG_STM32_CAN_REGDEBUG - If CONFIG_DEBUG_FEATURES is set, this will generate an
dump of all CAN registers.
STM32L-Discovery SPI Configuration
CONFIG_STM32_SPI_INTERRUPTS - Select to enable interrupt driven SPI
support. Non-interrupt-driven, poll-waiting is recommended if the
interrupt rate would be to high in the interrupt driven case.
CONFIG_STM32_SPIx_DMA - Use DMA to improve SPIx transfer performance.
Cannot be used with CONFIG_STM32_SPI_INTERRUPT.
Configurations
==============
Each STM32L-Discovery configuration is maintained in a sub-directory and
can be selected as follow:
tools/configure.sh STM32L-Discovery:<subdir>
Where <subdir> is one of the following sub-directories.
NOTE: These configurations use the mconf-based configuration tool. To
change any of these configurations 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.
Configuration sub-directories
-----------------------------
nsh:
---
Configures the NuttShell (nsh) located at apps/examples/nsh.
NOTES:
1. The serial console is on UART1 and NuttX LED support is enabled.
Therefore, you will need an external RS232 driver or TTL serial-to-
USB converter. The UART1 TX and RX pins should be available on
PA9 and PA10, respectively.
The serial console is configured for 57600 8N1 by default.
2. Support for NSH built-in applications is *not* enabled.
3. 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.
Build Setup:
CONFIG_HOST_WINDOWS=y : Builds under Windows
CONFIG_WINDOWS_CYGWIN=y : Using Cygwin
System Type:
CONFIG_ARM_TOOLCHAIN_GNU_EABI=y : GNU EABI toolchain for Windows
4. To enable SLCD support:
Board Selection:
CONFIG_ARCH_LEDS=n : Disable board LED support
Library Routines:
CONFIG_LIBC_SLCDCODEC=y : Enable the SLCD CODEC
System Type -> STM32 Peripheral Support:
CONFIG_STM32_LCD=y : Enable the Segment LCD
When the LCD is enabled and the LEDs are disabled, the USART1
serial console will automatically move to PB6 and PB7 (you will get
a compilation error if you forget to disable the LEDs).
SIGNAL FUNCTION LED CONNECTION
------ ---------- ---------- -----------
PB6 USART1_TX LED Blue P2, pin 8
PB7 USART1_RX LED Green P2, pin 7
To enable apps/examples/slcd to test the SLCD:
Binary Formats:
CONFIG_BINFMT_DISABLE=n : Don't disable binary support
CONFIG_BUILTIN=y : Enable support for built-in binaries
Application Configuration -> NSH Library:
CONFIG_NSH_BUILTIN_APPS=y : Enable builtin apps in NSH
CONFIG_NSH_ARCHINIT=y : Needed to initialize the SLCD
Application Configuration -> Examples:
CONFIG_EXAMPLES_SLCD=y : Enable apps/examples/slcd
To enable LCD debug output:
Device Drivers:
CONFIG_LCD=y : (Needed to enable LCD debug)
Build Setup -> Debug Options:
CONFIG_DEBUG_FEATURES=y : Enable debug features
CONFIG_DEBUG_INFO=y : Enable LCD debug
NOTE: At this point in time, testing of the SLCD is very limited because
there is not much in apps/examples/slcd. Certainly there are more bugs
to be found. There are also many segment-encoded glyphs in stm32_lcd.c
But there is a basically functional driver with a working test setup
that can be extended if you want a fully functional SLCD driver.
