git.rot13.org Git - simavr/blob - simavr/sim/sim_twi.c

   1 /*
   2         sim_twi.c
   3
   4         Internal TWI/i2c slave/master subsystem
   5
   6         Copyright 2008, 2009 Michel Pollet <buserror@gmail.com>
   7
   8         This file is part of simavr.
   9
  10         simavr is free software: you can redistribute it and/or modify
  11         it under the terms of the GNU General Public License as published by
  12         the Free Software Foundation, either version 3 of the License, or
  13         (at your option) any later version.
  14
  15         simavr is distributed in the hope that it will be useful,
  16         but WITHOUT ANY WARRANTY; without even the implied warranty of
  17         MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18         GNU General Public License for more details.
  19
  20         You should have received a copy of the GNU General Public License
  21         along with simavr.  If not, see <http://www.gnu.org/licenses/>.
  22  */
  23
  24 #include <stdlib.h>
  25 #include <string.h>
  26 #include <stdio.h>
  27 #include "sim_twi.h"
  28
  29 static void twi_bus_master_irq_notify(struct avr_irq_t * irq, uint32_t value, void * param)
  30 {
  31         twi_bus_t * bus = (twi_bus_t *)param;
  32         switch (irq->irq) {
  33                 case TWI_MASTER_STOP:
  34                         bus->peer = NULL;
  35                         break;
  36                 case TWI_MASTER_START:
  37                         bus->peer = NULL;
  38                         bus->ack = 0;
  39                         break;
  40                 case TWI_MASTER_MISO:
  41                         bus->ack = 0;
  42                         break;
  43                 case TWI_MASTER_MOSI:
  44                         bus->ack = 0;
  45                         break;
  46                 case TWI_MASTER_ACK:
  47                         if (!bus->peer) {
  48                         }
  49                         break;
  50         }
  51 }
  52
  53 static void twi_bus_slave_irq_notify(struct avr_irq_t * irq, uint32_t value, void * param)
  54 {
  55         twi_slave_t * slave = (twi_slave_t*)param;
  56         twi_bus_t * bus = slave->bus;
  57         switch (irq->irq) {
  58                 case TWI_SLAVE_MISO:
  59                         bus->latch = value;
  60                         break;
  61                 case TWI_SLAVE_ACK:
  62                         if (!bus->peer) {
  63                                 bus->peer = slave;
  64                                 printf("twi bus: slave %x selected\n", slave->address);
  65                         }
  66                         bus->ack = 0x80 | (value & 1);
  67                         break;
  68         }
  69 }
  70
  71 static void twi_slave_irq_notify(struct avr_irq_t * irq, uint32_t value, void * param)
  72 {
  73         twi_slave_t * slave = (twi_slave_t*)param;
  74         switch (irq->irq) {
  75                 case TWI_MASTER_STOP:
  76                         if (slave->match) {
  77                                 // we were target
  78                         }
  79                         slave->match = 0;
  80                         break;
  81                 case TWI_MASTER_START:
  82                         if ((value & 0xfe) == (slave->address & 0xfe)) {
  83                                 if (slave->match) {
  84                                         // restart
  85                                 }
  86                                 slave->match = 1;
  87                                 avr_raise_irq(slave->irq + TWI_SLAVE_ACK, 1);
  88                         }
  89                         break;
  90                 case TWI_MASTER_MISO:
  91                         break;
  92                 case TWI_MASTER_MOSI:
  93                         break;
  94                 case TWI_MASTER_ACK:
  95                         break;
  96         }
  97 }
  98
  99 void twi_bus_init(twi_bus_t * bus)
 100 {
 101         memset(bus, 0, sizeof(twi_bus_t));
 102         avr_init_irq(bus->irq, 0, TWI_MASTER_STATE_COUNT);
 103         for (int i = 0; i < TWI_MASTER_STATE_COUNT; i++)
 104                 avr_irq_register_notify(bus->irq + i, twi_bus_master_irq_notify, bus);
 105 }
 106
 107 void twi_bus_attach(twi_bus_t * bus, twi_slave_t * slave)
 108 {
 109         twi_slave_detach(slave);
 110         slave->bus = bus;
 111         slave->next = bus->slave;
 112         bus->slave = slave;
 113
 114         for (int i = 0; i < TWI_SLAVE_STATE_COUNT; i++)
 115                 avr_irq_register_notify(slave->irq + i, twi_bus_slave_irq_notify, slave);
 116         for (int i = 0; i < TWI_MASTER_STATE_COUNT; i++)
 117                 avr_irq_register_notify(bus->irq + i, twi_slave_irq_notify, slave);
 118 }
 119
 120 int twi_bus_start(twi_bus_t * bus, uint8_t address)
 121 {
 122         avr_raise_irq(bus->irq + TWI_MASTER_START, address);
 123         return bus->peer != NULL ? 1 : 0;
 124 }
 125
 126 void twi_bus_stop(twi_bus_t * bus)
 127 {
 128         avr_raise_irq(bus->irq + TWI_MASTER_STOP, 0);
 129 }
 130
 131
 132 void twi_slave_init(twi_slave_t * slave, uint8_t address, void * param)
 133 {
 134         memset(slave, 0, sizeof(twi_slave_t));
 135         slave->address = address;
 136 //      slave->param = param;
 137 }
 138
 139 void twi_slave_detach(twi_slave_t * slave)
 140 {
 141         if (!slave || !slave->bus)
 142                 return;
 143         twi_slave_t *s = slave->bus->slave;
 144         while (s) {
 145                 if (s->next == slave) {
 146                         // clear that, too
 147                         if (slave->bus->peer == slave)
 148                                 slave->bus->peer = NULL;
 149
 150                         s->next = slave->next;
 151                         slave->next = NULL;
 152                         slave->bus = NULL;
 153                         return;
 154                 }
 155                 s = s->next;
 156         }
 157 }
 158