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_pos = 0;
  48
  49 int main()
  50 {
  51         uint8_t clock_high = 0;
  52         uint8_t bits = 0;
  53         uint8_t n_bits = 8;
  54         uint8_t offset = 0;
  55         uint8_t i;
  56
  57         DDRD = 0x06;   // 00000110
  58         PORTD = 0xC0;  // 11000000
  59         DDRB = 0x20;   // 00100000
  60         PORTB = 0x1F;  // 00011111
  61
  62         serial_init(9600);
  63         lcd_init();
  64
  65         sei();
  66
  67         lcd_clear();
  68         for(i=0; i<20; ++i)
  69                 lcd_write('0');
  70
  71         while(1)
  72         {
  73                 uint8_t d_pins;
  74
  75                 d_pins = PIND;
  76
  77                 if(d_pins&BIT(CLOCK))
  78                 {
  79                         if(!clock_high)
  80                         {
  81                                 if(d_pins&BIT(LOAD))
  82                                 {
  83                                         offset = 0;
  84                                         bits = latch[0];
  85                                         n_bits = 8;
  86                                 }
  87                                 else
  88                                 {
  89                                         bits >>= 1;
  90                                         if(!--n_bits)
  91                                         {
  92                                                 ++offset;
  93                                                 bits = latch[offset];
  94                                                 n_bits = 8;
  95                                         }
  96                                 }
  97
  98                                 if(bits&1)
  99                                         PORTD |= BIT(DATA_OUT);
 100                                 else
 101                                         PORTD &= ~BIT(DATA_OUT);
 102
 103                                 clock_high = 1;
 104                         }
 105                 }
 106                 else if(clock_high)
 107                         clock_high = 0;
 108
 109                 if(d_pins&BIT(RESET))
 110                 {
 111                         uint8_t i;
 112                         for(i=0; i<128; ++i)
 113                                 latch[i] = input[i];
 114                 }
 115         }
 116 }
 117
 118 void receive(uint8_t c)
 119 {
 120         if(rx_fill==0xFF)
 121         {
 122                 if(c==':')
 123                         rx_fill = 0;
 124         }
 125         else if(c=='.')
 126         {
 127                 if(rx_fill>=4)
 128                 {
 129                         uint16_t offset;
 130                         uint8_t nibbles;
 131                         uint8_t i;
 132
 133                         offset = (decode_hex(rx_buf[0])<<8) | (decode_hex(rx_buf[1])<<4) | decode_hex(rx_buf[2]);
 134                         nibbles = (offset&3);
 135                         offset >>= 2;
 136                         if(rx_fill>3+nibbles)
 137                         {
 138                                 for(i=0; i<=nibbles; ++i)
 139                                 {
 140                                         uint16_t j = offset+nibbles-i;
 141                                         uint8_t shift = 4*(j&1);
 142                                         uint8_t bits = decode_hex(rx_buf[3+i]);
 143                                         input[j/2] = (input[j/2]&~(0xF<<shift)) | (bits<<shift);
 144                                         latch[j/2] = input[j/2];
 145                                 }
 146
 147                                 lcd_gotoxy(19-offset-nibbles, 0);
 148                                 for(i=0; i<=nibbles; ++i)
 149                                         lcd_write(rx_buf[3+i]);
 150                                 log_pos |= 0x80;
 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_pos%20, 1+log_pos/20);
 164         lcd_write(c);
 165         ++log_pos;
 166         if(log_pos>=60)
 167                 log_pos = 0;
 168         if(log_pos%20==0)
 169                 lcd_gotoxy(log_pos%20, 1+log_pos/20);
 170         lcd_write(255);
 171 }
 172
 173 SERIAL_SET_CALLBACK(receive)
 174
 175 uint8_t hexdigit(uint8_t n)
 176 {
 177         n &= 0xF;
 178         if(n<10)
 179                 return '0'+n;
 180         else
 181                 return 'A'+(n-0xA);
 182 }
 183
 184 uint8_t decode_hex(uint8_t c)
 185 {
 186         if(c>='0' && c<='9')
 187                 return c-'0';
 188         else if(c>='A' && c<='F')
 189                 return 0xA+(c-'A');
 190         else
 191                 return 0;
 192 }