BLUE-PILL-HUB

Features

• Carrier for the STM32 Blue Pill Board
  • STM32F103 CPU
• I2C Hub - PCA9544A
  • 4-channel I2C
  • Independent 3.3V/5V power for each I2C channel
  • Separate interrupts for each channel
• GVS (Ground,3.3V/Signal) connections for Blue Pill pins
• Reset switch

Blue Pill Module

• Blue Pill module schematic
• Install official support for STM32 bluepill on Arduino IDE and start programming and uploading sketches with STM32CubeProgrammer
• Nice description of the Blue Pill Boards
• Getting Started with STM32F103C8T6 Blue Pill
• Replace R10 with 1.5K resistor to fix STM32 USB D+ pull-up
• Working with Interrupts in STM32F103C8T6 Blue Pill Board

STM32F103 Arduino Pin Mapping

• Arduino pin 2 = B7
• Arduino pin 3 = B6
• Arduino pin 4 = B5
• Arduino pin 5 = B4
• Arduino pin 6 = B3
• Arduino pin 7 = A15
• Arduino pin 8 = A12
• Arduino pin 9 = A11
• Arduino pin 10 = A10
• Arduino pin 11 = A9
• Arduino pin 12 = A8
• Arduino pin 13 = B15
• Arduino pin 14 = B14
• Arduino pin 15 = B13
• Arduino pin 16 = null
• Arduino pin 17 = C13, onboard led, input only.
• Arduino pin 18 = C14
• Arduino pin 19 = C15
• Arduino pin 20 = A0
• Arduino pin 21 = A1
• Arduino pin 22 = A2
• Arduino pin 23 = A3
• Arduino pin 24 = A4
• Arduino pin 25 = A5
• Arduino pin 26 = A6
• Arduino pin 27 = A7
• Arduino pin 28 = B0
• Arduino pin 29 = B1
• Arduino pin 30 = B10
• Arduino pin 31 = B11

Connectors

J1 - 5V power

• DC jack
• 5V
• Center positive

J4 - 5V Power

• 5mm terminal block

J7 - I2C

• The I2C interface that goes to the I2C hub part

1. SCL (PB6)
2. SDA (PB7)
3. 3.3V
4. GND

P1 - 5V

• 2x4 header with 5V from H2 (Rev 4 card)

P2 - Vbattery

• Battery power to the Blue Pill board

1. GND
2. Vbat

P3 - FTDI connector (Rev X1-X3)

• To cable to FTDI wires swap pins 4 and 5 in cable
• FTDI card jumper has to be set to 3.3V since STM32 has 3.3V signal levels

1. GND
2. N/C
3. VCC (to H8 pin 2)
4. TX (to Blue Pill RX) (PA10 pin on STM32)
5. RX (to Blue Pill Tx) (PA9 pin on STM32)
6. RESET*

P3 - FTDI Module (Rev 4 or higher)

• Cheap FT232 module pinout

P4, P5, P6, P7 - I2C Interfaces #0-#3

1. INT*
2. SCL
3. SDA
4. VCC
5. GND

P8 - SPI

1. PA6 (MISO)
2. 3.3V
3. PA5 (SCK)
4. PA7 (MOSI)
5. RES
6. GND

P11/P12 - GVS Connector

• Ground, Power, Signal pins

1. n/c
2. PC13
3. PC14
4. PC15
5. PA0
6. PA1
7. PA2
8. PA3
9. PA4
10. PA5/SCK1
11. PA6/MISO1
12. PA7/MOSI1
13. PB0
14. PB1
15. PB10
16. PB11

P12/P13 - GVS Connector

• Ground, Power, Signal pins

1. n/c
2. PB9
3. PB8 = I2C_INT
4. PB7 = I2C_SDA1
5. PB6 = I2C_SCL
6. PB5
7. PB4
8. PB3
9. PA15
10. PA12
11. PA11
12. RX
13. TX
14. PA8
15. PB15
16. PB14
17. PB13
18. PB12

Headers

H1 - 3.3V (Rev X1-X3)

• Install to power 3.3V from regulator

H1 - 3.3V source select

• 1-2 power from 5V to 3.3V regulator
• 2-3 Power from Blue Pill board 3.3V regulator

H2 - 5V Jumper (Rev X1-X3)

• Install to connect J4 and J1 5V

H2 - 5V Power Source (Rev 4 or higher)

• T-shaped header
• Up - Power 5V from BluePill Hub USB power
• Left - Power 5V from DC Jack
• Down - Power 5V from FTDI 5V

H3, H4, H5, H6 - I2C Power

• Select the power to the I2C interface
• Install in one of the two positions to power external I2C interface from the board
• Remove if power comes in from external I2C interface

1. 3.3V
2. 5V

H7 - 3.3V from Blue Pill module 3.3V regulator

• Install = power on-board 3.3V circuitry from regulator on Blue Pill module
  • H8 should not be installed if H7 is installed

H8 - Power from FTDI

• 1-2 = 3.3V from FTDI (don't ever do this)
• 2-3 = 5V from FTDI (probably don't do this)
• H7 should not be installed if H8 is installed

H9 - I2C Mux Chip Address Offset

• 2x3 header
• Select the address offset of the PCA9544A I2C hub
• Base address = 0x70
• A0-A2 - address offset jumpers
• Install for 0, remove for 1
• Typical use 0x71 = remove A0, install A1, A2

Switches

SW1 - Reset Switch

• Press to reset Blue Pill board

SW2 - Power Switch (Rev 4)

• Switches on/off J1, J4 power source

Schematic

• Schematic - Rev X3 Board
• Schematic - Rev 4 Board

Drivers

• STM32 examples
• Installing the STM32 USB Bootloader - Youtube video

Uploading Code

• FTDI connection to Blue Pill Hub FTDI connector
  • FTDI TX (to Blue Pill RX) (PA10 pin on STM32)
  • FTDI RX (to Blue Pill Tx) (PA9 pin on STM32)
• Set Switch (or jumper) on Blue Pill module set towards center of card to download

• In Arduino IDE,
  • Tools
    • Board "Generic..."
    • Upload method: "Serial..."
    • Port: [the comm port]

• Upload code
  • Takes a while
• Set Switch (or jumper) on Blue Pill module set towards edge of card to run
• Press reset button

Testing

• Arduino Based Test Station
• ODAS Tester Github Repo

Programming

• ST-LINK V2
• FLASHER-STM32 - STM32 Flash loader demonstrator (UM0462)
• From AN3155

Rev 4 Board

• Change FTDI to Module
• Added power switch for DC Jack or 5mm jumper block

Rev 1 Board

Assembly Sheet

• Blue Pill Hub Assembly Sheet Rev 4
• Blue Pill Hub Assembly Sheet - Rev 3