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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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82
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 level = set_irq_level(DISABLE_INTERRUPTS); /* Timing sensitive */
int i;
unsigned char crc;
/* 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
* it is set low as output and switched between input and output mode.
@ -162,45 +163,52 @@ int ds2411_read_id(struct ds2411_id *id)
/* Read presence pulse - line should be pulled low at proper time by the
slave device */
if (GPIO_READ & DS2411_BIT)
if ((GPIO_READ & DS2411_BIT) == 0)
{
/* Trsth + 1 - 66 = Tpdhmax + Tpdlmax + Trecmin + 1 - 66 */
DELAY(240);
/* ds2411 should be ready for data transfer */
/* Send Read ROM command */
ds2411_write_byte(0x33);
/* Read ROM serial number and CRC */
i = 0, crc = 0;
do
{
unsigned char byte = ds2411_read_byte();
((unsigned char *)id)[i] = byte;
crc = ds2411_calc_crc(crc ^ byte);
}
while (++i < 8);
/* Check that family code is ok */
if (id->family_code != 0x01)
{
logf("ds2411: invalid family code=%02X", (unsigned)id->family_code);
i = DS2411_INVALID_FAMILY_CODE;
}
/* Check that CRC was ok */
else if (crc != 0) /* Because last loop eors the CRC with the resulting CRC */
{
logf("ds2411: invalid CRC=%02X", (unsigned)id->crc);
i = DS2411_INVALID_CRC;
}
else
{
/* Good ID read */
i = DS2411_OK;
}
}
else
{
logf("ds2411: no presence pulse");
return DS2411_NO_PRESENCE;
i = DS2411_NO_PRESENCE;
}
/* Trsth + 1 - 66 = Tpdhmax + Tpdlmax + Trecmin + 1 - 66 */
DELAY(240);
set_irq_level(level);
/* ds2411 should be ready for data transfer */
/* Send Read ROM command */
ds2411_write_byte(0x33);
/* Read ROM serial number and CRC */
i = 0, crc = 0;
do
{
unsigned char byte = ds2411_read_byte();
((unsigned char *)id)[i] = byte;
crc = ds2411_calc_crc(crc ^ byte);
}
while (++i < 8);
/* Check that family code is ok */
if (id->family_code != 0x01)
{
logf("ds2411: invalid family code=%02X", (unsigned)id->family_code);
return DS2411_INVALID_FAMILY_CODE;
}
/* Check that CRC was ok */
if (crc != 0) /* Because last loop eors the CRC with the resulting CRC */
{
logf("ds2411: invalid CRC=%02X", (unsigned)id->crc);
return DS2411_INVALID_CRC;
}
/* Good ID read */
return DS2411_OK;
return i;
} /* ds2411_read_id */