ir-probe/test.c

   1 #include "util.h"
   2
   3 #include <libopencm3/cm3/cortex.h>
   4 #include <libopencm3/cm3/nvic.h>
   5 #include <libopencm3/cm3/systick.h>
   6 #include <libopencm3/stm32/rcc.h>
   7 #include <libopencm3/stm32/gpio.h>
   8 #include <libopencm3/stm32/usart.h>
   9
  10 static void clock_setup(void)
  11 {
  12         rcc_clock_setup_in_hse_8mhz_out_72mhz();
  13
  14         rcc_periph_clock_enable(RCC_GPIOB);
  15         rcc_periph_clock_enable(RCC_GPIOC);
  16         rcc_periph_clock_enable(RCC_USART1);
  17
  18         rcc_periph_reset_pulse(RST_GPIOB);
  19         rcc_periph_reset_pulse(RST_GPIOC);
  20         rcc_periph_reset_pulse(RST_USART1);
  21 }
  22
  23 static void gpio_setup(void)
  24 {
  25         // PC13 = BluePill LED
  26         gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
  27         gpio_clear(GPIOC, GPIO13);
  28
  29         // PB9 = SFH5110 output (5V tolerant)
  30         gpio_set_mode(GPIOC, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO9);
  31 }
  32
  33 static void usart_setup(void)
  34 {
  35         gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX);
  36
  37         usart_set_baudrate(USART1, 115200);
  38         usart_set_databits(USART1, 8);
  39         usart_set_stopbits(USART1, USART_STOPBITS_1);
  40         usart_set_mode(USART1, USART_MODE_TX_RX);
  41         usart_set_parity(USART1, USART_PARITY_NONE);
  42         usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
  43
  44         usart_enable(USART1);
  45 }
  46
  47 static void tick_setup(void)
  48 {
  49         systick_set_reload(0xffffff);
  50         systick_counter_enable();
  51         systick_interrupt_disable();
  52         systick_clear();
  53 }
  54
  55 static u16 get_bit(void)
  56 {
  57         return !gpio_get(GPIOB, GPIO9);
  58 }
  59
  60 #define MAX_SAMPLES 1024
  61 u32 samples[MAX_SAMPLES];
  62
  63 int main(void)
  64 {
  65         clock_setup();
  66         gpio_setup();
  67         usart_setup();
  68         tick_setup();
  69
  70         debug_puts("\n\n### Infrared Remote Control receiver ###\n\n");
  71
  72         for (;;) {
  73                 gpio_set(GPIOC, GPIO13);
  74
  75                 if (get_bit()) {
  76                         debug_puts("Waiting for silence\n");
  77                         while (get_bit())
  78                                 ;
  79                 }
  80                 debug_puts("Ready...");
  81
  82                 u16 last = 0;
  83                 uint nsamp = 0;
  84                 u32 start;
  85
  86                 do {
  87                         start = systick_get_value();
  88                         last = get_bit();
  89                 } while (!last);
  90
  91                 gpio_clear(GPIOC, GPIO13);
  92
  93                 for (;;) {
  94                         u32 now;
  95                         u16 curr;
  96                         uint len;
  97                         do {
  98                                 now = systick_get_value();
  99                                 len = (start - now) & 0xffffff;
 100                                 if (len > 5000000) {
 101                                         samples[nsamp++] = len;
 102                                         goto timeout;
 103                                 }
 104                                 curr = get_bit();
 105                         } while (curr == last);
 106                         samples[nsamp++] = len;
 107                         if (nsamp >= MAX_SAMPLES)
 108                                 break;
 109                         start = now;
 110                         last = curr;
 111                 }
 112
 113         timeout:
 114                 for (uint i=0; i<nsamp; i++) {
 115                         debug_putc(i ? ' ' : '\n');
 116                         debug_printf("%u", (samples[i] + CPU_CLOCK_MHZ - 1) / CPU_CLOCK_MHZ);   // in μs
 117                 }
 118                 debug_putc('\n');
 119         }
 120
 121         return 0;
 122 }