firmware/s88w-r.c

   1 /* $Id$
   2
   3 This file is part of the MSP Märklin suite
   4 Copyright © 2010  Mikkosoft Productions, Mikko Rasa
   5 Distributed under the GPL
   6
   7 Firmware for wireless S88 receiver module
   8
   9 S88 pinout:
  10 1 - DATA
  11 2 - GND
  12 3 - CLOCK
  13 4 - LOAD
  14 5 - RESET
  15 6 - POWER
  16
  17 ATMega pinout:
  18 D0 - serial RX
  19 D1 - serial TX
  20 D2 - S88 DATA
  21 D3 - S88 CLOCK
  22 D4 - S88 LOAD
  23 D5 - S88 RESET
  24 */
  25
  26 #include <avr/io.h>
  27 #include <avr/interrupt.h>
  28 #include "lcd.h"
  29 #include "serial.h"
  30 #include "delay.h"
  31
  32 #define DATA_OUT PORTD2
  33 #define CLOCK    PIND3
  34 #define LOAD     PIND4
  35 #define RESET    PIND5
  36
  37 #define BIT(n)   (1<<(n))
  38
  39 void receive(uint8_t);
  40 uint8_t hexdigit(uint8_t);
  41 uint8_t decode_hex(uint8_t);
  42
  43 volatile uint8_t rx_buf[7];
  44 volatile uint8_t rx_fill = 0xFF;
  45 volatile uint8_t input[128] = { 0 };
  46 volatile uint8_t latch[128] = { 0 };
  47 uint8_t log_row = 0;
  48 uint8_t log_col = 0;
  49
  50 int main()
  51 {
  52         uint8_t clock_high = 0;
  53         uint8_t bits = 0;
  54         uint8_t n_bits = 8;
  55         uint8_t offset = 0;
  56         uint8_t i;
  57
  58         DDRD = 0x06;   // 00000110
  59         PORTD = 0xC0;  // 11000000
  60         DDRB = 0x20;   // 00100000
  61         PORTB = 0x1F;  // 00011111
  62
  63         serial_init(9600);
  64         lcd_init();
  65
  66         sei();
  67
  68         lcd_clear();
  69         for(i=0; i<20; ++i)
  70                 lcd_write('0');
  71
  72         while(1)
  73         {
  74                 uint8_t d_pins;
  75
  76                 d_pins = PIND;
  77
  78                 if(d_pins&BIT(CLOCK))
  79                 {
  80                         if(!clock_high)
  81                         {
  82                                 if(d_pins&BIT(LOAD))
  83                                 {
  84                                         offset = 0;
  85                                         bits = latch[0];
  86                                         n_bits = 8;
  87                                 }
  88                                 else
  89                                 {
  90                                         bits >>= 1;
  91                                         if(!--n_bits)
  92                                         {
  93                                                 ++offset;
  94                                                 bits = latch[offset];
  95                                                 n_bits = 8;
  96                                         }
  97                                 }
  98
  99                                 if(bits&1)
 100                                         PORTD |= BIT(DATA_OUT);
 101                                 else
 102                                         PORTD &= ~BIT(DATA_OUT);
 103
 104                                 clock_high = 1;
 105                         }
 106                 }
 107                 else if(clock_high)
 108                         clock_high = 0;
 109
 110                 if(d_pins&BIT(RESET))
 111                 {
 112                         uint8_t i;
 113                         for(i=0; i<128; ++i)
 114                                 latch[i] = input[i];
 115                 }
 116         }
 117 }
 118
 119 void receive(uint8_t c)
 120 {
 121         if(rx_fill==0xFF)
 122         {
 123                 if(c==':')
 124                         rx_fill = 0;
 125         }
 126         else if(c=='.')
 127         {
 128                 if(rx_fill>=4)
 129                 {
 130                         uint16_t offset;
 131                         uint8_t nibbles;
 132                         uint8_t i;
 133
 134                         offset = (decode_hex(rx_buf[0])<<8) | (decode_hex(rx_buf[1])<<4) | decode_hex(rx_buf[2]);
 135                         nibbles = (offset&3);
 136                         offset >>= 2;
 137                         if(rx_fill>3+nibbles)
 138                         {
 139                                 for(i=0; i<=nibbles; ++i)
 140                                 {
 141                                         uint16_t j = offset+nibbles-i;
 142                                         uint8_t shift = 4*(j&1);
 143                                         uint8_t bits = decode_hex(rx_buf[3+i]);
 144                                         input[j/2] = (input[j/2]&~(0xF<<shift)) | (bits<<shift);
 145                                         latch[j/2] = input[j/2];
 146                                 }
 147
 148                                 lcd_gotoxy(19-offset-nibbles, 0);
 149                                 for(i=0; i<=nibbles; ++i)
 150                                         lcd_write(rx_buf[3+i]);
 151                         }
 152                 }
 153                 rx_fill = 0xFF;
 154         }
 155         else
 156         {
 157                 if(rx_fill<sizeof(rx_buf))
 158                         rx_buf[rx_fill++] = c;
 159                 else
 160                         rx_fill = 0xFF;
 161         }
 162
 163         lcd_gotoxy(log_col, 1+log_row);
 164         lcd_write(c);
 165         ++log_col;
 166         if(log_col>=20)
 167         {
 168                 log_col = 0;
 169                 ++log_row;
 170                 if(log_row>=3)
 171                         log_row = 0;
 172                 lcd_gotoxy(log_col, 1+log_row);
 173         }
 174         lcd_write(255);
 175 }
 176
 177 SERIAL_SET_CALLBACK(receive)
 178
 179 uint8_t hexdigit(uint8_t n)
 180 {
 181         n &= 0xF;
 182         if(n<10)
 183                 return '0'+n;
 184         else
 185                 return 'A'+(n-0xA);
 186 }
 187
 188 uint8_t decode_hex(uint8_t c)
 189 {
 190         if(c>='0' && c<='9')
 191                 return c-'0';
 192         else if(c>='A' && c<='F')
 193                 return 0xA+(c-'A');
 194         else
 195                 return 0;
 196 }