arducontrol/s88.c

   1 #include <avr/io.h>
   2 #include "interface.h"
   3 #include "ringbuffer.h"
   4 #include "s88.h"
   5 #include "serial.h"
   6 #include "timer.h"
   7
   8 #define RESET PORTD4
   9 #define LOAD PORTD5
  10 #define CLOCK PORTD6
  11 #define DATA PIN7
  12 #define BIT(x) (1<<(x))
  13
  14 static volatile uint8_t s88_read_count = 0;
  15 static uint8_t s88_read_bit = 0;
  16 static volatile uint8_t s88_read_phase = 0;
  17 static uint8_t s88_data = 0;
  18 static RINGBUFFER(s88_buffer, 8);
  19 static uint8_t s88_out_index = 0;
  20
  21 void s88_init(void)
  22 {
  23         DDRD = (DDRD&0x0F)|0x70;
  24         PORTD &= 0x0F;
  25
  26         timer_start_hz(0, 80000, 1);
  27 }
  28
  29 void s88_check(void)
  30 {
  31         uint8_t count = ringbuffer_fill(s88_buffer);
  32         if(count>=4 || (count>0 && !s88_read_count))
  33         {
  34                 uint8_t reply[10];
  35
  36                 reply[0] = S88_DATA;
  37                 reply[1] = s88_out_index;
  38                 for(uint8_t i=0; i<count; ++i)
  39                         reply[2+i] = ringbuffer_pop(s88_buffer);
  40                 interface_send(reply, 2+count);
  41                 s88_out_index += count;
  42         }
  43 }
  44
  45 uint8_t s88_command(const uint8_t *cmd_buf, uint8_t cmd_length)
  46 {
  47         if(cmd_buf[0]==S88_READ)
  48         {
  49                 if(cmd_length!=2)
  50                         return LENGTH_ERROR;
  51
  52                 while(s88_read_count || s88_read_phase) ;
  53
  54                 s88_out_index = 0;
  55                 s88_read_phase = 0xF0;
  56                 s88_read_count = cmd_buf[1];
  57         }
  58         else
  59                 return INVALID_COMMAND;
  60
  61         return COMMAND_OK;
  62 }
  63
  64 static inline void s88_tick(void)
  65 {
  66         if(s88_read_phase==0)
  67         {
  68                 if(!s88_read_count || ringbuffer_space(s88_buffer)==0)
  69                         return;
  70
  71                 PORTD |= BIT(CLOCK);
  72         }
  73         else if(s88_read_phase==1)
  74         {
  75                 uint8_t bit = (PIND>>7)&1;
  76                 s88_data = (s88_data<<1)|bit;
  77                 ++s88_read_bit;
  78                 if(s88_read_bit==8)
  79                 {
  80                         ringbuffer_push(s88_buffer, s88_data);
  81
  82                         --s88_read_count;
  83                         s88_read_bit = 0;
  84                 }
  85         }
  86         else if(s88_read_phase==2)
  87                 PORTD &= ~BIT(CLOCK);
  88         else if(s88_read_phase>3)
  89         {
  90                 if(s88_read_phase==0xF0)
  91                         PORTD |= BIT(LOAD);
  92                 else if(s88_read_phase==0xF4)
  93                         PORTD |= BIT(CLOCK);
  94                 else if(s88_read_phase==0xF6)
  95                         PORTD &= ~BIT(CLOCK);
  96                 else if(s88_read_phase==0xFA)
  97                         PORTD |= BIT(RESET);
  98                 else if(s88_read_phase==0xFC)
  99                         PORTD &= ~BIT(RESET);
 100                 else if(s88_read_phase==0xFF)
 101                 {
 102                         s88_data = (PIND>>7)&1;
 103                         ++s88_read_bit;
 104                         PORTD &= ~BIT(LOAD);
 105                 }
 106                 ++s88_read_phase;
 107                 return;
 108         }
 109
 110         s88_read_phase = (s88_read_phase+1)&3;
 111 }
 112
 113 TIMER_SET_CALLBACK(0, s88_tick)