STM32F4 + Codec V2
STM32F4 Codec V2 - Rev - Assembled
STM32F4 Codec V2 - Rev A PCB Rendering
This is a small (3.7" x 2.4") board with an STM32F405RGT6 MCU, a Wolfson WM8731
codec and a variety of I/O resources to support development of embedded
audio effects applications. This is a revision of the the
STM32F4 Codec board.
- 32-bit ARM Cortex-M4 CPU with floating point and 168MHz clock
- 192kB SRAM
- 1MB Flash
- 14 Timers
- 3 SPI (2 with I2S capability)
- 3 I2C
- 6 USART+UART
- 2 USB OTG
- 2 CAN
- 51 GPIO pins
- 16 Chl to 3x 12-bit ADCs
- 2 12-bit DAC
- Note: Footprint is compatible with other 64-pin QFP parts in the
STM32F405/7 family for additional resources.
- Onboard 3.3V Regulator (4.75V - 15V input range)
- Separate Analog 3.3V Supply
WM8731 Stereo Audio Codec
- USB mini-AB OTG connector
- Micro SD slot (SDIO interface)
- Power and User LEDs
- Reset button
- 6-pin SWD compatible programming interface
- 4-pin serial connector
- I2C serial EEPROM
- 4 ratiometric pots on 2 analog inputs
- Rotary encoder with pushbutton
- Adafruit 1.8" 128x160 color LCD
- 7 lines MCU analog/digital I/O
- AC-coupled line-level stereo audio I/O on 2 3.5mm jacks
- Headphone and microphone audio on 2 3.5mm jacks
Interfaces and Jumpers
- JP101: STM32 Boot mode jumper. Install to run bootloader.
- JP102: USB VBUS selector. Choose bus power, self power or OTG.
- J201: Power: 4-pin keyed power connector (+5V only).
- J101: USB. Mini-AB connector for USB device/host.
- J102: Micro SD slot.
- J103: 4-pin serial connector.
- J105: ST-Link SWD. 6-pin in-system programming connector.
- J106: 8-pin 0.1" header to unused GPIO on MCU.
- CONN201: 3.5mm stereo line-level audio output.
- CONN202: 3.5mm stereo line-level audio input.
- CONN203: 3.5mm microphone input.
- CONN204: 3.5mm headphone output.
- SW101: Reset button - tied directly to the MCU reset input. Handy way to
quickly reboot your MCU after flashing new code into it.
- LED201: Power indicator - lights up when 3.3V is present.
- LED101: User GPIO - connected to GPIOB-8,9. Useful for diagnostics.
- VR101,VR102, VR103, VR104: 10K ratiometric pot inputs to 2 ADC input channels.
For development I use a basic make / gcc flow with my favorite text editor which runs
well in either Linux, Mac OS X or Windows. For downloading to hardware and debugging
the ST Discovery boards with STLINK V2 are well supported under Open OCD. Here's
a list of where to get the tools:
- 2012-12-29: Started Revised Layout.
- 2014-05-08: Major schematic revisions.
- 2014-05-16: Order PC boards.
- 2014-05-30: PC boards received from fab.
- 2014-06-07: Assembled, testing features.
- Codec Line in/out, LCD, ADC, Serial, Encoder works.
- New headphone driver works.
- Mic input requires minor wiring fix but works.
- Power Jack footprint needs corrections, but usable.
- USB DFU Bootloader not enumerating.
- 2014-06-10: USB MIDI device works.
- 2014-06-27: SDIO works.
- 2014-06-30: USB MIDI host works.
- 2014-07-01: EEPROM works.
- 2014-07-02: Fix Xtal caps - USB DFU Bootloader works.
- 2014-07-03: Update schematic, layout, order Rev A boards.
- 2014-07-18: Rev A boards back from fab. Tested and all features working.
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