===================== ST STM32L Discovery ===================== This page 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. .. 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 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 N/C N/C LED_SIGNAL In a signal handler N/C N/C LED_ASSERTION An assertion failed N/C N/C LED_PANIC The system has crashed OFF Blinking LED_IDLE STM32 is is sleep mode N/U =================== ======================= ======== ======== 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 ========= 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 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. 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. Configurations ============== Each STM32L-Discovery configuration is maintained in a sub-directory and can be selected as follow: tools/configure.sh STM32L-Discovery: Where 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. SLCD. 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