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 LCD_DISABLE PINB4
  38
  39 #define BIT(n)   (1<<(n))
  40
  41 void receive(uint8_t);
  42 uint8_t hexdigit(uint8_t);
  43 uint8_t decode_hex(uint8_t);
  44
  45 volatile uint8_t rx_buf[7];
  46 volatile uint8_t rx_fill = 0xFF;
  47 volatile uint8_t input[128] = { 0 };
  48 volatile uint8_t latch[128] = { 0 };
  49 volatile uint8_t lcd_enabled = 0;
  50 uint8_t log_row = 0;
  51 uint8_t log_col = 0;
  52
  53 int main()
  54 {
  55         uint8_t clock_high = 0;
  56         uint8_t bits = 0;
  57         uint8_t n_bits = 8;
  58         uint8_t offset = 0;
  59         uint8_t i;
  60
  61         DDRD = 0x06;   // 00000110
  62         PORTD = 0xC0;  // 11000000
  63         DDRB = 0x20;   // 00100000
  64         PORTB = 0x1F;  // 00011111
  65
  66         serial_init(9600);
  67         lcd_init();
  68
  69         sei();
  70
  71         while(1)
  72         {
  73                 uint8_t b_pins, d_pins;
  74
  75                 b_pins = PINB;
  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                 if(b_pins&BIT(LCD_DISABLE))
 118                 {
 119                         if(lcd_enabled)
 120                         {
 121                                 lcd_enabled = 0;
 122
 123                                 lcd_clear();
 124                         }
 125                 }
 126                 else if(!lcd_enabled)
 127                 {
 128                         lcd_enabled = 1;
 129                         log_row = 0;
 130                         log_col = 0;
 131
 132                         lcd_clear();
 133                         for(i=0; i<20; ++i)
 134                                 lcd_write(hexdigit(input[9-i/2]>>(4-i%2*4)));
 135                         lcd_gotoxy(0, 1);
 136                         lcd_write(255);
 137                 }
 138         }
 139 }
 140
 141 void receive(uint8_t c)
 142 {
 143         if(rx_fill==0xFF)
 144         {
 145                 if(c==':')
 146                         rx_fill = 0;
 147         }
 148         else if(c=='.')
 149         {
 150                 if(rx_fill>=4)
 151                 {
 152                         uint16_t offset;
 153                         uint8_t nibbles;
 154                         uint8_t i;
 155
 156                         offset = (decode_hex(rx_buf[0])<<8) | (decode_hex(rx_buf[1])<<4) | decode_hex(rx_buf[2]);
 157                         nibbles = (offset&3);
 158                         offset >>= 2;
 159                         if(rx_fill>3+nibbles)
 160                         {
 161                                 for(i=0; i<=nibbles; ++i)
 162                                 {
 163                                         uint16_t j = offset+nibbles-i;
 164                                         uint8_t shift = 4*(j&1);
 165                                         uint8_t bits = decode_hex(rx_buf[3+i]);
 166                                         input[j/2] = (input[j/2]&~(0xF<<shift)) | (bits<<shift);
 167                                         latch[j/2] = input[j/2];
 168                                 }
 169
 170                                 if(lcd_enabled)
 171                                 {
 172                                         lcd_gotoxy(19-offset-nibbles, 0);
 173                                         for(i=0; i<=nibbles; ++i)
 174                                                 lcd_write(rx_buf[3+i]);
 175                                 }
 176                         }
 177                 }
 178                 rx_fill = 0xFF;
 179         }
 180         else
 181         {
 182                 if(rx_fill<sizeof(rx_buf))
 183                         rx_buf[rx_fill++] = c;
 184                 else
 185                         rx_fill = 0xFF;
 186         }
 187
 188         if(lcd_enabled)
 189         {
 190                 lcd_gotoxy(log_col, 1+log_row);
 191                 lcd_write(c);
 192                 ++log_col;
 193                 if(log_col>=20)
 194                 {
 195                         log_col = 0;
 196                         ++log_row;
 197                         if(log_row>=3)
 198                                 log_row = 0;
 199                         lcd_gotoxy(log_col, 1+log_row);
 200                 }
 201                 lcd_write(255);
 202         }
 203 }
 204
 205 SERIAL_SET_CALLBACK(receive)
 206
 207 uint8_t hexdigit(uint8_t n)
 208 {
 209         n &= 0xF;
 210         if(n<10)
 211                 return '0'+n;
 212         else
 213                 return 'A'+(n-0xA);
 214 }
 215
 216 uint8_t decode_hex(uint8_t c)
 217 {
 218         if(c>='0' && c<='9')
 219                 return c-'0';
 220         else if(c>='A' && c<='F')
 221                 return 0xA+(c-'A');
 222         else
 223                 return 0;
 224 }