dc33-retro-tech-addon/firmware/retro_tech_fw/code/main.c

/*
 * RETRO TECH 2025
 * GAT Addon Firmware
 * by true
 *
 * version 0.1.1
 * Last Update 20250723
 *
 * code was made for different random addons I designed for dc32,
 * then adapted to each one. it worked OK. this code was then more
 * or less directly ported to another MCU. so things might be a mess.
 *
 * I had only a few hours on and off over a week to get the code done.
 * lots of shit was copied from demo code and adapted to work. certainly
 * isn't the best way to get this done.
 *
 * I know I could save some power, but seeing as all the badges burn it in
 * LEDs and almost nobody else power optimizes their badge code, who cares?
 *
 * sorry. wasn't procrastination I swear. all the ideas were last minute.
 */

#include <ch32x035.h>
#include <stdint.h>

#include "src/adc.h"
#include "src/btn.h"
#include "src/config.h"
#include "src/i2c_soft.h"
#include "src/led.h"
#include "src/led_rgbprog.h"
#include "src/rand.h"
#include "src/ui.h"

#include "global.h"



/*
void systick_init(void)
{
    SysTick->CMP = (SystemCoreClock / 512) - 1;     // we want a 512Hz interrupt
    SysTick->CNT = 0;                               // clear counter
    SysTick->CTLR = 0xF;                            // start counter in /1 mode, enable interrupts, auto-reset counter
    SysTick->SR = 0;                                // clear count comparison flag

    NVIC_EnableIRQ(SysTicK_IRQn);                   // enable interrupt
}
*/

void awu_init(void)
{
    // these magic numbers set a ~498.6Hz update rate
    // 48000000 (HSI) / 1024 / Prescale / Window
    AWU_SetPrescaler(AWU_Prescaler_2);
    AWU_SetWindowValue(47);
    AutoWakeUpCmd(ENABLE);

    // in order to fire AWU interrupt, enable EXTI interrupt on rising edge on EXTI line 27.
    // this isn't explicitly stated in the DS, but AWU interrupt == EXTI line27 interrupt.
    EXTI->RTENR  = EXTI_RTENR_TR27;
    EXTI->INTENR = EXTI_INTENR_MR27;
    
    NVIC_EnableIRQ(AWU_IRQn);    
}

void gpio_init()
{
    GPIO_InitTypeDef gpio = {0};

    // only one GPIO speed on this bad boy, and it must be defined
    gpio.GPIO_Speed = GPIO_Speed_50MHz;

    // jogwheel digital inputs (PA4-PA6) (active low)
    gpio.GPIO_Mode = GPIO_Mode_IPU;
    gpio.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_5 | GPIO_Pin_6;
    GPIO_Init(GPIOA, &gpio);

    // lightsense LED cathode (PA7, A8)
    gpio.GPIO_Mode = GPIO_Mode_AIN;
    gpio.GPIO_Pin = GPIO_Pin_7;
    GPIOA->BCR = GPIO_Pin_7;
    GPIO_Init(GPIOA, &gpio);

    // potentiometer (PB1; A9)
    gpio.GPIO_Pin = GPIO_Pin_1;
    GPIO_Init(GPIOB, &gpio);

    // lightsense LED anode (PB7)
    gpio.GPIO_Mode = GPIO_Mode_Out_PP;
    gpio.GPIO_Pin = GPIO_Pin_7;
    GPIOB->BCR = GPIO_Pin_7;
    GPIO_Init(GPIOB, &gpio);

    // USB (unused in application...for now) (PC16, PC17)

    // debug (not changed in application) (PC18, PC19)

    // EEP_WP EEPROM write protect (PA9) (active high)
    // IS_SDB IS31FL3729 shutdown pin (PC3) (active low)
    gpio.GPIO_Mode = GPIO_Mode_Out_PP;
    GPIOA->BCR = GPIO_Pin_9;
    gpio.GPIO_Pin = GPIO_Pin_9;
    GPIO_Init(GPIOA, &gpio);
    GPIOC->BCR = GPIO_Pin_3;
    gpio.GPIO_Pin = GPIO_Pin_3;
    GPIO_Init(GPIOC, &gpio);

    // I2C SDA, SCL for addon header (PA10, PA11)
    gpio.GPIO_Mode = GPIO_Mode_AF_PP;
    gpio.GPIO_Pin = GPIO_Pin_10 | GPIO_Pin_11;
    GPIO_Init(GPIOA, &gpio);
    
    // software I2C SDA, SCL for on-board devices (PA0, PA1)
    gpio.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIOA->BCR = GPIO_Pin_0 | GPIO_Pin_1;
    gpio.GPIO_Pin = GPIO_Pin_0 | GPIO_Pin_1;
    GPIO_Init(GPIOA, &gpio);

    // UART RX/TX on addon header (not currently used) (PA2, PA3)
    gpio.GPIO_Mode = GPIO_Mode_IPU;
    gpio.GPIO_Pin = GPIO_Pin_2 | GPIO_Pin_3;
    GPIO_Init(GPIOA, &gpio);
}


// here we go
int main(void)
{
    // configure core
    NVIC_PriorityGroupConfig(NVIC_PriorityGroup_1);

    // enable peripheral clocks
    RCC_APB1PeriphClockCmd( RCC_APB1Periph_PWR   | RCC_APB1Periph_I2C1, ENABLE);
    RCC_APB2PeriphClockCmd( RCC_APB2Periph_AFIO  | RCC_APB2Periph_GPIOA |
                            RCC_APB2Periph_GPIOB | RCC_APB2Periph_GPIOC |
                            RCC_APB2Periph_ADC1  | RCC_APB2Periph_TIM1, ENABLE);

    // configure gpio pins, including buttons (need button for settings reset)
    gpio_init();

    // get saved settings, or reset if BTN1 is pushed
    i2cm_init();
    userconf_load((BTN_PORT->INDR & (1 << BTN2_PIN)) ? 0 : 1);

    // configure hardware
    adc_init();
    btn_init();
    led_init();

    // configure random
    tinymt32_init(&tinymt32_s, DBGMCU_GetCHIPID() | userconf.checksum);

    // configure UI
    ui_init();

    // configure auto-wakeup to run at ~498Hz
    awu_init();

    // set up LEDs initially
    led_rgb_firstrun();

    // do system shit
    while(1) {
        __WFI();

        // after sending LEDs, run LED render program
        // to update the LED buffer for next time
        // we have approx 7ms to render... plenty of time
        if ((ticnt & 0x3) == 0) {
            ui_render();
        }
    }
}