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_GPIOA);
  15         rcc_periph_clock_enable(RCC_GPIOB);
  16         rcc_periph_clock_enable(RCC_GPIOC);
  17         rcc_periph_clock_enable(RCC_USART1);
  18
  19         rcc_periph_reset_pulse(RST_GPIOA);
  20         rcc_periph_reset_pulse(RST_GPIOB);
  21         rcc_periph_reset_pulse(RST_GPIOC);
  22         rcc_periph_reset_pulse(RST_USART1);
  23 }
  24
  25 static void gpio_setup(void)
  26 {
  27         // PC13 = BluePill LED
  28         gpio_set_mode(GPIOC, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO13);
  29         gpio_clear(GPIOC, GPIO13);
  30
  31         // PB9 = SFH5110 output (5V tolerant)
  32         gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO9);
  33 }
  34
  35 static void usart_setup(void)
  36 {
  37         gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO9);
  38
  39         usart_set_baudrate(USART1, 115200);
  40         usart_set_databits(USART1, 8);
  41         usart_set_stopbits(USART1, USART_STOPBITS_1);
  42         usart_set_mode(USART1, USART_MODE_TX_RX);
  43         usart_set_parity(USART1, USART_PARITY_NONE);
  44         usart_set_flow_control(USART1, USART_FLOWCONTROL_NONE);
  45
  46         usart_enable(USART1);
  47 }
  48
  49 static void tick_setup(void)
  50 {
  51         systick_set_reload(0xffffff);
  52         systick_counter_enable();
  53         systick_interrupt_disable();
  54         systick_clear();
  55 }
  56
  57 static u16 get_bit(void)
  58 {
  59         return !gpio_get(GPIOB, GPIO9);
  60 }
  61
  62 #define MAX_SAMPLES 1024
  63 u32 samples[MAX_SAMPLES];
  64
  65 int main(void)
  66 {
  67         clock_setup();
  68         gpio_setup();
  69         usart_setup();
  70         tick_setup();
  71
  72         debug_puts("\n\n### Infrared Remote Control receiver ###\n\n");
  73
  74         for (;;) {
  75                 gpio_set(GPIOC, GPIO13);
  76
  77                 if (get_bit()) {
  78                         debug_puts("Waiting for silence\n");
  79                         while (get_bit())
  80                                 ;
  81                 }
  82                 debug_puts("Ready...");
  83
  84                 u16 last = 0;
  85                 uint nsamp = 0;
  86                 u32 start;
  87
  88                 do {
  89                         start = systick_get_value();
  90                         last = get_bit();
  91                 } while (!last);
  92
  93                 gpio_clear(GPIOC, GPIO13);
  94
  95                 for (;;) {
  96                         u32 now;
  97                         u16 curr;
  98                         uint len;
  99                         do {
 100                                 now = systick_get_value();
 101                                 len = (start - now) & 0xffffff;
 102                                 if (len > 5000000) {
 103                                         samples[nsamp++] = len;
 104                                         goto timeout;
 105                                 }
 106                                 curr = get_bit();
 107                         } while (curr == last);
 108                         samples[nsamp++] = len;
 109                         if (nsamp >= MAX_SAMPLES)
 110                                 break;
 111                         start = now;
 112                         last = curr;
 113                 }
 114
 115         timeout:
 116                 for (uint i=0; i<nsamp; i++) {
 117                         debug_putc(i ? ' ' : '\n');
 118                         debug_printf("%u", (samples[i] + CPU_CLOCK_MHZ - 1) / CPU_CLOCK_MHZ);   // in μs
 119                 }
 120                 debug_putc('\n');
 121         }
 122
 123         return 0;
 124 }