JMCU Nucleo-F103RB devboard

Development Board Power

The board can be powered from STM32 Nucleo or from terminal 8-56V. To select a power source, you must install the appropriate jumper PWR SOURCE 5V.

The ground is shared between the debug board and the Nucleo board. The 3.3V supply voltage is generated from a 5V source using a linear regulator (LDO) installed on the Nucleo board. When installing a large number of JXM modules, it is recommended to use only an external 8 power supply.

Buttons and indication

To control the boot mode of the microcontroller, the "BOOT0" button is used, which controls the BOOT0 pin of the microcontroller: while holding down the "BOOT0" button during power-up or hardware reset of the microcontroller, the built-in STM32 bootloader is loaded, which allows you to write firmware via UART or I2C. When pressed, a high logic level is set at the BOOT0 input of the microcontroller.

There is a red LED JXM_RESET - a signal to reset the JXM modules. Each JXM module has a green LED JXM_INT - interrupt indicator.

All other indicators are available on the STM32 Nucleo board.

RESET

Hardware reset of the microcontroller is carried out from the button on the STM32 Nucleo debug board.

EEPROM and FRAM

Addresses of memory chips on the I2C bus:

EEPROM CAT24C64 64Kbit address 7-bit 0x57

FRAM FM24CL64B 64Kbit address 7-bit 0x56

This I2C bus also has a pin connector for connecting additional devices.

Pin Purpose
1 +3.3V
2 +5V
3 GND
4 INT_I2C_SCL
5 INT_I2C_SDA

JXM module pinout 8-pin connector

Pin Purpose
1 +5V
2 +3.3V
3 GND
4 ID_VOLTAGE
5 I2C_SDA
6 I2C_SCL
7 HW_RESET
8 INT/BOOT

JXM module pinout 4-pin connector

Pin Purpose
1 IO_3
2 IO_2
3 IO_4
4 IO_1

STM32F103RB pin assignment

STM32 pin Name
PB2 JMCU_JXM_RESET
PC1 JMCU_JXM_1_INT
PC2 JMCU_JXM_2_INT
PC3 JMCU_JXM_3_INT
PC4 JMCU_JXM_4_INT
PC5 JMCU_JXM_5_INT
PC6 JMCU_JXM_6_INT
PC7 JMCU_JXM_7_INT
PC8 JMCU_JXM_8_INT
PC9 JMCU_JXM_9_INT
PC10 JMCU_JXM_10_INT
PC11 JMCU_JXM_11_INT
PB12 JMCU_JXM_12_INT
PB13 JMCU_JXM_13_INT
PB14 JMCU_JXM_14_INT
PB15 JMCU_JXM_15_INT
PA6 JMCU_CANPHY_HWVER
PC0 JMCU_CAN_RTR
PA8 JMCU_CAN_HDC
PA11 JMCU_CAN_RX
PA12 JMCU_CAN_TX
PA2 JMCU_CONSOLE_TX
PA3 JMCU_CONSOLE_RX
PA9 JMCU_CPU_UART_TX
PA10 JMCU_CPU_UART_RX
PB3 JMCU_INT_SPI_SCK
PB4 JMCU_INT_SPI_MISO
PB5 JMCU_INT_SPI_MOSI
PD2 JMCU_INT_SPI_CS_FLASH
PB8 JMCU_JXM_I2C_SCL
PB9 JMCU_JXM_I2C_SDA
PB10 JMCU_INT_I2C_SCL
PB11 JMCU_INT_I2C_SDA
PA5 JMCU_STATUS_LED
PC13 JMCU_BTN_FN
PA0 JMCU_AIN_EXT_VOLTAGE
PA1 JMCU_AIN_5V_VOLTAGE
PA4 JMCU_AIN_5V_CURRENT