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PRG32 Hardware

This page summarizes the classroom reference wiring. See hardware/README.md for the hardware directory map and board scaffolds.

Base Hardware

Quantity Item Purpose
1 ESP32-C6 development board PRG32 RISC-V host
1 ILI9341 SPI TFT or supported display video output
1 digital joystick module local input
1 optional setup button force setup mode without holding A+B

Reference Display And Input Wiring

These pins match main/prg32_config.h for the ESP32-C6 physical ILI9341 build. They are the same display wiring used by the Arduino/Adafruit validation sketch.

ESP32-C6 ILI9341 TFT / control
3V3 VCC
GND GND
GPIO7 MOSI
GPIO2 MISO / touch DO
GPIO6 SCLK
GPIO10 CS
GPIO1 DC
GPIO0 RST
GPIO5 BL
ESP32-C6 Input
GPIO18 P1 LEFT
GPIO19 P1 RIGHT
GPIO3 P1 UP
GPIO13 P1 DOWN
GPIO20 P1 SELECT
GPIO21 P1 A
GPIO22 P1 B
GPIO15 passive buzzer

GPIO14 is still accepted by the firmware as an older START/SELECT wiring alias, but new classroom harnesses should use GPIO20 for SELECT.

The LCD backlight defaults to active-high. If a specific breakout uses an active-low backlight transistor, set PRG32_LCD_BACKLIGHT_ACTIVE_LEVEL to 0 in main/prg32_config.h.

Onboard RGB LED

PRG32 can drive a WS2812-style onboard RGB LED through:

prg32_rgb_led_init(gpio);
prg32_rgb_led_set(red, green, blue);

Many ESP32-C6 development boards wire the onboard RGB LED to GPIO8. The reference PRG32 display harness already uses GPIO8 for LCD D/C, so PRG32_PIN_RGB_LED defaults to -1 and the LED is disabled. Enable it only when your board exposes the LED on a free GPIO or your display wiring has been changed accordingly. The setup audio menu can use the LED as a spectrum-style VU meter.

Mono Audio

ESP32-C6 MAX98357A
3V3 or 5V VIN
GND GND
GPIO4 BCLK
GPIO11 LRC / WS
GPIO23 DIN
not wired by default SD / MODE optional

Connect one 4-8 ohm speaker to the MAX98357A speaker + and - outputs.

The default audio Kconfig pins avoid the reference display, joystick, and passive buzzer wiring. If a breakout needs explicit SD/shutdown control, assign CONFIG_PRG32_AUDIO_I2S_SD_GPIO to another unused GPIO before flashing.

On the Adafruit MAX98357A breakout, SD also selects the channel mode. Leave it in the breakout's default enabled state for mono, or drive it from the optional SD GPIO. Do not tie SD directly to GND because that shuts the amplifier down. PRG32 mono audio is carried as duplicated left/right I2S slots, so a single MAX98357A works whether the breakout averages both slots or selects one slot.

Use the physical ESP32-C6 defaults when flashing classroom hardware:

idf.py -B build-esp32c6 -D SDKCONFIG=build-esp32c6/sdkconfig -D SDKCONFIG_DEFAULTS=sdkconfig.defaults set-target esp32c6
idf.py -B build-esp32c6 -D SDKCONFIG=build-esp32c6/sdkconfig -D SDKCONFIG_DEFAULTS=sdkconfig.defaults build flash monitor

The QEMU defaults are for the ESP32-C3 virtual display path and intentionally disable physical I2S audio output.

Stereo Audio

Stereo uses two MAX98357A boards on the same I2S bus:

ESP32-C6 Left MAX98357A Right MAX98357A
3V3 or 5V VIN VIN
GND GND GND
GPIO4 BCLK BCLK
GPIO11 LRC / WS LRC / WS
GPIO23 DIN DIN
optional SD GPIO SD SD

Configure the left board for left output and the right board for right output. Breakout pin labels vary; verify the vendor pinout before soldering.

Safety Notes

  • Do not connect speaker outputs to headphones or line inputs.
  • Keep speaker wires short during breadboard tests.
  • Use a power source that can supply the speaker current.
  • Reassign audio GPIOs if they conflict with the display or joystick wiring in a specific classroom kit.