qemu/hw/max111x.c
balrog c824cacdb1 Maxim MAX1110/1111 ADC chip.
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@2755 c046a42c-6fe2-441c-8c8c-71466251a162
2007-04-30 02:14:00 +00:00

137 lines
2.7 KiB
C

/*
* Maxim MAX1110/1111 ADC chip emulation.
*
* Copyright (c) 2006 Openedhand Ltd.
* Written by Andrzej Zaborowski <balrog@zabor.org>
*
* This code is licensed under the GNU GPLv2.
*/
#include <vl.h>
struct max111x_s {
qemu_irq interrupt;
uint8_t tb1, rb2, rb3;
int cycle;
int input[8];
int inputs, com;
};
/* Control-byte bitfields */
#define CB_PD0 (1 << 0)
#define CB_PD1 (1 << 1)
#define CB_SGL (1 << 2)
#define CB_UNI (1 << 3)
#define CB_SEL0 (1 << 4)
#define CB_SEL1 (1 << 5)
#define CB_SEL2 (1 << 6)
#define CB_START (1 << 7)
#define CHANNEL_NUM(v, b0, b1, b2) \
((((v) >> (2 + (b0))) & 4) | \
(((v) >> (3 + (b1))) & 2) | \
(((v) >> (4 + (b2))) & 1))
uint32_t max111x_read(void *opaque)
{
struct max111x_s *s = (struct max111x_s *) opaque;
if (!s->tb1)
return 0;
switch (s->cycle ++) {
case 1:
return s->rb2;
case 2:
return s->rb3;
}
return 0;
}
/* Interpret a control-byte */
void max111x_write(void *opaque, uint32_t value)
{
struct max111x_s *s = (struct max111x_s *) opaque;
int measure, chan;
/* Ignore the value if START bit is zero */
if (!(value & CB_START))
return;
s->cycle = 0;
if (!(value & CB_PD1)) {
s->tb1 = 0;
return;
}
s->tb1 = value;
if (s->inputs == 8)
chan = CHANNEL_NUM(value, 1, 0, 2);
else
chan = CHANNEL_NUM(value & ~CB_SEL0, 0, 1, 2);
if (value & CB_SGL)
measure = s->input[chan] - s->com;
else
measure = s->input[chan] - s->input[chan ^ 1];
if (!(value & CB_UNI))
measure ^= 0x80;
s->rb2 = (measure >> 2) & 0x3f;
s->rb3 = (measure << 6) & 0xc0;
if (s->interrupt)
qemu_irq_raise(s->interrupt);
}
static struct max111x_s *max111x_init(qemu_irq cb)
{
struct max111x_s *s;
s = (struct max111x_s *)
qemu_mallocz(sizeof(struct max111x_s));
memset(s, 0, sizeof(struct max111x_s));
s->interrupt = cb;
/* TODO: add a user interface for setting these */
s->input[0] = 0xf0;
s->input[1] = 0xe0;
s->input[2] = 0xd0;
s->input[3] = 0xc0;
s->input[4] = 0xb0;
s->input[5] = 0xa0;
s->input[6] = 0x90;
s->input[7] = 0x80;
s->com = 0;
return s;
}
struct max111x_s *max1110_init(qemu_irq cb)
{
struct max111x_s *s = max111x_init(cb);
s->inputs = 8;
return s;
}
struct max111x_s *max1111_init(qemu_irq cb)
{
struct max111x_s *s = max111x_init(cb);
s->inputs = 4;
return s;
}
void max111x_set_input(struct max111x_s *s, int line, uint8_t value)
{
if (line >= s->inputs) {
printf("%s: There's no input %i\n", __FUNCTION__, line);
return;
}
s->input[line] = value;
}