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74123 Fixes:

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* Clear behaviour to follow datasheet.
* Avoid recursive calls when setting a/b/clear lines from callback
This commit is contained in:
Couriersud 2008-11-03 01:16:39 +00:00
parent b29e06704b
commit 17b6c56de9
1 changed files with 18 additions and 6 deletions
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24
src/emu/machine/74123.c
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@ -71,12 +71,21 @@ static int timer_running(ttl74123_t *chip)
}
static TIMER_CALLBACK( output_callback )
{
const device_config *device = ptr;
ttl74123_t *chip = get_safe_token(device);
chip->intf->output_changed_cb(device, 0, param);
}
static void set_output(const device_config *device)
{
ttl74123_t *chip = get_safe_token(device);
int output = timer_running(chip);
chip->intf->output_changed_cb(device, 0, output);
timer_set( attotime_zero, (void *) device, output, output_callback );
if (LOG) logerror("74123 %s: Output: %d\n", device->tag, output);
}
@ -85,8 +94,10 @@ static void set_output(const device_config *device)
static TIMER_CALLBACK( clear_callback )
{
const device_config *device = ptr;
ttl74123_t *chip = get_safe_token(device);
int output = timer_running(chip);
set_output(device);
chip->intf->output_changed_cb(device, 0, output);
}
@ -154,14 +165,15 @@ WRITE8_DEVICE_HANDLER( ttl74123_clear_w )
{
ttl74123_t *chip = get_safe_token(device);
/* clear the output if A=LO, B=HI and falling edge on clear */
if (!data && chip->clear && chip->b && !chip->a && !chip->clear)
/* start/regtrigger pulse if B=HI and A=LO and rising edge on clear */
if (data && !chip->a && chip->b && !chip->clear)
start_pulse(device);
else if (!data) /* clear the output */
{
timer_adjust_oneshot(chip->timer, attotime_zero, 0);
if (LOG) logerror("74123 #%s: Cleared\n", device->tag );
}
chip->clear = data;
}
@ -185,7 +197,7 @@ static DEVICE_START( ttl74123 )
chip->intf = device->static_config;
assert_always(chip->intf, "No interface specified");
assert_always((chip->intf->connection_type == TTL74123_GROUNDED) && (chip->intf->cap >= CAP_U(0.01)), "Only capacitors >= 0.01uF supported for GROUNDED type");
assert_always((chip->intf->connection_type != TTL74123_GROUNDED) || (chip->intf->cap >= CAP_U(0.01)), "Only capacitors >= 0.01uF supported for GROUNDED type");
assert_always(chip->intf->cap >= CAP_P(1000), "Only capacitors >= 1000pF supported ");
chip->timer = timer_alloc(clear_callback, (void *) device);