ROM2/coinmech.c

   1 #include "coinmech.h"
   2 #include "vend.h"
   3
   4 #define COINMECH_ID   0x20
   5
   6 volatile u8 last_byte;
   7 volatile u8 packet_pos;
   8 volatile u16 value_1;
   9 volatile u8 value_2;
  10 volatile u8 dec_point;
  11
  12 volatile u16 coin_value;
  13 u8 item_cost;
  14 volatile bool have_change;
  15
  16 u8 parity_test(u8 c) {
  17         u8 parity = 0;
  18         for (parity = 0; c; c = c>>1) {
  19                 if (c&1) parity = !parity;
  20         }
  21         return parity;
  22 }
  23
  24 bool parity_good(u8 c) {
  25
  26 /*
  27  * parity_good truth table:
  28  *
  29  *      | parity_test(c)
  30  *      | 0   1
  31  * -----+---------
  32  * R8 0 | 1   0
  33  *    1 | 0   1
  34  *
  35  * equates to even parity?
  36  */
  37
  38         u8 R8 = (_io_ports[M6811_SCCR1] & M6811_R8)?1:0;
  39         u8 p = parity_test(c)?1:0;
  40         return R8 == p;
  41 }
  42
  43 void send_byte(u8 c) {
  44         last_byte = c;
  45         while (!(_io_ports[M6811_SCSR] & M6811_TDRE)); /* wait for TD register empty */
  46
  47         if (parity_test(c))
  48                 bset((void*)&_io_ports[M6811_SCCR1], M6811_T8);
  49         else
  50                 bclr((void*)&_io_ports[M6811_SCCR1], M6811_T8);
  51 }
  52
  53 #define IS_CTRL(x) (x & 0x10) /* true if this packet is a control packet */
  54 void sci_interrupt_coinmech() {
  55         u8 in;
  56         in = _io_ports[M6811_SCDR];
  57
  58         /* test for framing errors & parity bit */
  59         if (_io_ports[M6811_SCSR] & M6811_FE || !parity_good(in)) {
  60                 _io_ports[M6811_SCDR]; /* read of register req'd to clear FE */
  61                 send_byte(0xff); /* request a retransmit */
  62                 return;
  63         }
  64
  65         /* all bytes must have the correct ID in the 3 MSBs */
  66         if ((in & 0xe0) != COINMECH_ID) return;
  67
  68         /* we have a good packet */
  69         if (in == 0x3f) {
  70                 /* retransmit was requested */
  71                 send_byte(last_byte);
  72                 return;
  73         }
  74
  75         if (packet_pos != 0 || IS_CTRL(in)) {
  76                 in &= 0x0f;
  77                 switch (in) {
  78                         case 0x01:
  79                                 /* just reply with ack */
  80                                 /* original firmware does something with link master price holding */
  81                                 send_byte(0x00);
  82                         case 0x02:
  83                                 /* write back how much change to give, or 0xfe to hold it. */
  84                                 if (item_cost) {
  85                                         send_byte(item_cost / value_2);
  86                                 } else
  87                                         send_byte(0xfe);
  88                                 break;
  89                         case 0x03:
  90                                 /* hmmm, maybe we're sposed to do something here. firmware doesnt */
  91                                 /* and just sets a random bit - something like "changer in use"?  */
  92                                 break;
  93                         case 0x08:
  94                                 /* start of packet */
  95                                 packet_pos = 1;
  96                                 send_byte(0x00);
  97                                 break;
  98                         default:
  99                                 /* just ack it and move on */
 100                                 send_byte(0x00);
 101                 }
 102         } else {
 103                 in &= 0x0f;
 104                 switch (packet_pos) {
 105                         case 1: value_1  = in;           break;
 106                         case 2: value_1 |= in << 4;      break;
 107                         case 3: value_1 |= in << 8;      break;
 108                         case 4: value_1 |= in << 12;     break;
 109                         case 5: value_2  = in;           break;
 110                         case 6: value_2 |= in << 4;      break;
 111                         case 7: dec_point = in;          break;
 112                         case 8: have_change = (in&0x01); break;
 113                         default:
 114                                         if (packet_pos == 9) {
 115                                                 packet_pos = 0;
 116                                                 coin_value = value_1*value_2;
 117                                         }
 118                                         /* hmmm, else? */
 119                 }
 120                 packet_pos++;
 121                 send_byte(0x00); /* ack */
 122         }
 123 }
 124
 125 void coin_eat() {
 126         coin_cost(coin_value); /* eat everything */
 127 }
 128
 129 void coin_cost(u16 cost) {
 130         item_cost = cost;
 131         while(coin_value); /* wait until coin mech cleared */
 132 }
 133
 134 void coinmech_init() {
 135         packet_pos = 0;
 136         value_1 = value_2 = 0;
 137         dec_point = 0;
 138         coin_value = 0;
 139         item_cost = 0;
 140         have_change = 0;
 141         _io_ports[M6811_SCCR1] = 0x10;
 142         _io_ports[M6811_SCCR2] = 0x2e;
 143         _io_ports[M6811_BAUD] = 0x03;
 144         send_byte(0xff);
 145 }