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Fix a late error that only let it read at default CPU frequency. Disable interrupts during ds2411 read since it's timing sensitive.

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@12724 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Michael Sevakis 2007-03-11 14:33:16 +00:00
parent 89a38d4273
commit 94c4724420
1 changed files with 45 additions and 37 deletions
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32
firmware/target/coldfire/iaudio/x5/ds2411-x5.c
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@ -134,11 +134,12 @@ static unsigned char ds2411_read_byte(void)
*/ */
int ds2411_read_id(struct ds2411_id *id) int ds2411_read_id(struct ds2411_id *id)
{ {
int level = set_irq_level(DISABLE_INTERRUPTS); /* Timing sensitive */
int i; int i;
unsigned char crc; unsigned char crc;
/* Initialize delay factor based on loop time: 3*(uS-1) + 3 */ /* Initialize delay factor based on loop time: 3*(uS-1) + 3 */
ds2411_delay_factor = MIN(cpu_frequency / (1000000*3), 1); ds2411_delay_factor = MAX(cpu_frequency / (1000000*3), 1);
/* Init GPIO 1 wire bus for bit banging with a pullup resistor where /* Init GPIO 1 wire bus for bit banging with a pullup resistor where
* it is set low as output and switched between input and output mode. * it is set low as output and switched between input and output mode.
@ -162,12 +163,8 @@ int ds2411_read_id(struct ds2411_id *id)
/* Read presence pulse - line should be pulled low at proper time by the /* Read presence pulse - line should be pulled low at proper time by the
slave device */ slave device */
if (GPIO_READ & DS2411_BIT) if ((GPIO_READ & DS2411_BIT) == 0)
{ {
logf("ds2411: no presence pulse");
return DS2411_NO_PRESENCE;
}
/* Trsth + 1 - 66 = Tpdhmax + Tpdlmax + Trecmin + 1 - 66 */ /* Trsth + 1 - 66 = Tpdhmax + Tpdlmax + Trecmin + 1 - 66 */
DELAY(240); DELAY(240);
@ -191,16 +188,27 @@ int ds2411_read_id(struct ds2411_id *id)
if (id->family_code != 0x01) if (id->family_code != 0x01)
{ {
logf("ds2411: invalid family code=%02X", (unsigned)id->family_code); logf("ds2411: invalid family code=%02X", (unsigned)id->family_code);
return DS2411_INVALID_FAMILY_CODE; i = DS2411_INVALID_FAMILY_CODE;
} }
/* Check that CRC was ok */ /* Check that CRC was ok */
if (crc != 0) /* Because last loop eors the CRC with the resulting CRC */ else if (crc != 0) /* Because last loop eors the CRC with the resulting CRC */
{ {
logf("ds2411: invalid CRC=%02X", (unsigned)id->crc); logf("ds2411: invalid CRC=%02X", (unsigned)id->crc);
return DS2411_INVALID_CRC; i = DS2411_INVALID_CRC;
}
else
{
/* Good ID read */
i = DS2411_OK;
}
}
else
{
logf("ds2411: no presence pulse");
i = DS2411_NO_PRESENCE;
} }
/* Good ID read */ set_irq_level(level);
return DS2411_OK;
return i;
} /* ds2411_read_id */ } /* ds2411_read_id */