BPIO

BluePill IO adapter with ABMT-Node.

Flash precompiled firmware

• Set outside juper to 1 and press reset. Call:
  stm32flash -w firmware/release/bpio_fw_id0.bin -v -g 0x0 /dev/ttyUSB0
  PA9 -> RX-USB; PA10 -> TX-USB
  Unlock device:
  stm32flash -k /dev/ttyUSB0
stm32flash -u /dev/ttyUSB0
• or:
  • Get and install stlink utils from https://github.com/stlink-org/stlink
  • Unlock device: st-flash --reset write firmware/release/option_bytes_default.bin 0x1FFFF800
  • Flash firmware st-flash write firmware/release/bpio_fw_id0.bin 0x8000000
• or: pyocd load firmware/release/bpio_fw_id0.bin -f 4000000 -e chip -t stm32f103rc

udev rules for all ID's

SUBSYSTEM=="tty", ATTRS{idVendor}=="1f00", ATTRS{idProduct}=="2012", ATTRS{product} == "BPIO0", SYMLINK+="ttyBPIO0"
SUBSYSTEM=="tty", ATTRS{idVendor}=="1f00", ATTRS{idProduct}=="2012", ATTRS{product} == "BPIO1", SYMLINK+="ttyBPIO1"
SUBSYSTEM=="tty", ATTRS{idVendor}=="1f00", ATTRS{idProduct}=="2012", ATTRS{product} == "BPIO2", SYMLINK+="ttyBPIO2"
SUBSYSTEM=="tty", ATTRS{idVendor}=="1f00", ATTRS{idProduct}=="2012", ATTRS{product} == "BPIO3", SYMLINK+="ttyBPIO3"
SUBSYSTEM=="tty", ATTRS{idVendor}=="1f00", ATTRS{idProduct}=="2012", ATTRS{product} == "BPIO4", SYMLINK+="ttyBPIO4"

I2C

You can read max 128 Bytes per request (sizeof(i2c_response)). Delay per request is around 2ms with steppers enabled and 1ms without.

PWM

Input is a float value form 0 to 1. Internaly the all PWM outputs have a resolution of 1024. A prescaler can be configured to change the frequency. A prescaler of 0 results in a frequency of 72MHz/1024/( 0 + 1 ) -> 70.3kHz. A prescaler of 1 results in a pwm frequency of 72MHz/1024/( 1 +1) -> 35.2kHz.

Analog

Outputs a float value form 0 to 1.

Kown Issues

• Modemmanager blocks device -> uninstall usless deamon
• BluePill cant be flashed.
  Many new BluePills ar'e locked and the option bytes need to be changed to flash via st-link.
  You can call 'flash_default_option_bytes.sh' (You may need a new version stlink from https://github.com/stlink-org/stlink. Debians current version is to old. "v1.7.0-201-g254a525" worked for me.
  Or you use stm32flash and flash via serial port instead of st-flash. Remove read an write protection with -k -u.
• Many BluePills have a wrong (10k) pull up resistor at the USB-Port. In some cases this interrupts the detection when plugging in the device. Fix: Add a 1.8k resister from 3.3V to pin A12.
• I2C errors like not connected devices break stepper control.

Changes V1 -> V2

• 72Mhz instead of 48Mhz (PWM freq changes!)
• I2C pin change from B6/B7 to B8/B9
• Stepper4 moved from A15/B3 to C14/C5

Compile

Install mbed

• see https://os.mbed.com/docs/mbed-os/v6.15/build-tools/install-and-set-up.html
• pip install mbed-cli

Copy mbed-os

• Download release https://os.mbed.com/mbed-os/releases/
• Move contained folder to 'mbed-os'

Compile

mbed compile --target BLUE_PILL --toolchain GCC_ARM