Maple Mini and the mbed¶

Sparkfun used to sell a board which provides an affordable (still available for less than $4 from some on-line sellers) and flexible way for users to try out new ideas and build prototypes. The board is equipped with an STM32F103CBT6 microcontroller compatible with the NUCLEO-F103RB platform.

Microcontroller features¶

• STM32F103CBT6 in LQFP48 package
• ARM®32-bit Cortex®-M3 CPU
• 72 MHz max CPU frequency
• VDD from 2.0 V to 3.6 V
• 128 KB Flash
• 20 KB SRAM
• GPIO (32) with external interrupt capability
• 12-bit ADC (2) with 10 channels
• RTC
• Timers (4)
• I2C (2)
• USART (3)
• SPI (2)
• USB 2.0 full-speed
• CAN

Board features¶

• Small foot-print
• Flexible board power supply: USB VBUS or external source (3.0V-12V)
• User LED: LED1
• Two push buttons: RESET, USER BUTTON
• Mini-B USB connector

Maple mini board pinout¶

Courtesy of Wim Huiskamp Zoom in

LED1=PB_1   SERIAL_TX=PA_2  I2C_SCL=PB_6  SPI_MOSI=PA_7  PWM_OUT=PB_3
            SERIAL_RX=PA_3  I2C_SDA=PB_7  SPI_MISO=PA_6
                                          SPI_SCK =PA_5
                                          SPI_CS  =PB_6

Using mbed on-line compiler to build programs for the Maple mini¶

• Create a program as if it was for a NUCLEO-F103RB board (select NUCLEO-F103RB as target platform in the on-line compiler).

• Import the mbed-MapleMini library into your project.

• Add #include "MapleMini.h" to main.cpp before #include "mbed.h" (position matters!) and call confSysClock function at the begin of main function.

#include "MapleMini.h"
#include "mbed.h"
 
Serial      pc(PA_2, PA_3);
DigitalOut  myled(LED1);
 
int main() {
    confSysClock();     // Configure system clock (72MHz HSE clock, 36MHz APB1 peripheral clock)
    while(1) {
        myled = 1;      // turn the LED on
        wait(0.2);      // 200 ms
        myled = 0;      // turn the LED off
        wait(1.0);      // 1 sec
        pc.printf("Blink\r\n");
    }
}

Programming the Maple mini board¶

You can use the NUCLEO virtual disk to program the Maple Mini (drag and drop programming). To do that, an additional NUCLEO board is needed (any type equipped with ST-LINK/V2-1 will do).

• Remove the two jumpers from the CN2 connector as illustrated in Figure 8:
  
  
• Connect the NUCLEO board's CN4 debug connector to the Maple Mini board:
  
  
  
  
• Pins connected:

• Provide power for the Maple Mini board.
  
  
• Connect the NUCLEO board via USB cable to your PC.
  
  
• To program the Maple Mini board, click on the Compile button and save the binary to the NUCLEO virtual disk .
  
  For more details have a look at the User Manual, chapter 6.2.4 Using ST-LINK/V2-1 to program and debug an external STM32 application.
  
  

Using serial port (for debugging)¶

• Connect an FTDI or similar USB-Serial converter to your PC and to an on-board serial port (for example PA_2, PA_3). Make sure you connect the on-board TX pin to the converter's RX pin and the on-board RX pin to the converter's TX pin.

• In your code, create a Serial object (using TX and RX pin names of the connected serial port).

• Use printf function to send serial messages to the connected PC.
  
  

Off-line compilation and debugging with CooCox CoIDE¶

• Export your program from the mbed on-line compiler to CooCox CoIDE.

• Save the file into a folder on you PC's hard drive and unzip.
  
  
• Run CoIDE and open the project.
  
  
• To setup the debugger, open the Debugger tab and use the following settings:
  
  
  

Happy coding and debugging.