diff options
Diffstat (limited to 'firmware/target/coldfire/iaudio/x5')
| -rw-r--r-- | firmware/target/coldfire/iaudio/x5/ds2411-x5.c | 70 |
1 files changed, 39 insertions, 31 deletions
diff --git a/firmware/target/coldfire/iaudio/x5/ds2411-x5.c b/firmware/target/coldfire/iaudio/x5/ds2411-x5.c index a8b2ae705c..bb85c8e00e 100644 --- a/firmware/target/coldfire/iaudio/x5/ds2411-x5.c +++ b/firmware/target/coldfire/iaudio/x5/ds2411-x5.c @@ -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) { - logf("ds2411: no presence pulse"); - return DS2411_NO_PRESENCE; - } + /* Trsth + 1 - 66 = Tpdhmax + Tpdlmax + Trecmin + 1 - 66 */ + DELAY(240); - /* Trsth + 1 - 66 = Tpdhmax + Tpdlmax + Trecmin + 1 - 66 */ - DELAY(240); + /* ds2411 should be ready for data transfer */ - /* ds2411 should be ready for data transfer */ + /* Send Read ROM command */ + ds2411_write_byte(0x33); - /* Send Read ROM command */ - ds2411_write_byte(0x33); + /* Read ROM serial number and CRC */ + i = 0, crc = 0; - /* 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); - do - { - unsigned char byte = ds2411_read_byte(); - ((unsigned char *)id)[i] = byte; - crc = ds2411_calc_crc(crc ^ byte); + /* 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; + } } - while (++i < 8); - - /* Check that family code is ok */ - if (id->family_code != 0x01) + else { - logf("ds2411: invalid family code=%02X", (unsigned)id->family_code); - return DS2411_INVALID_FAMILY_CODE; + logf("ds2411: no presence pulse"); + i = DS2411_NO_PRESENCE; } - /* 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; - } + set_irq_level(level); - /* Good ID read */ - return DS2411_OK; + return i; } /* ds2411_read_id */ |