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added support for DS18S20 #148

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added support for DS18S20 #148

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23 changes: 18 additions & 5 deletions src/onewire.c
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Original file line number Diff line number Diff line change
Expand Up @@ -285,6 +285,8 @@ static int32_t OneWire_Work(void) {
static uint8_t mystate = 0;
uint8_t scratch[9];
int32_t retval = 0;
int numBytesToRead = 4;
int16_t tmp;

if (mystate == 0) {
uint32_t save = VIC_DisableIRQ();
Expand All @@ -302,14 +304,25 @@ static int32_t OneWire_Work(void) {
uint32_t save = VIC_DisableIRQ();
selectdevbyidx(i);
xferbyte(OW_READ_SCRATCHPAD);
for (uint32_t iter = 0; iter < 4; iter++) { // Read four bytes
uint8_t family = owdeviceids[i][0];
if (family == OW_FAMILY_TEMP3) numBytesToRead = 7; // AD: for the DS18S20 read 7 bytes into scratchpad
for (uint32_t iter = 0; iter < numBytesToRead; iter++) { // Read bytes into scratch
scratch[iter] = xferbyte(0xff);
}
VIC_RestoreIRQ(save);
int16_t tmp = scratch[1]<<8 | scratch[0];
devreadout[i] = tmp;
tmp = scratch[3]<<8 | scratch[2];
extrareadout[i] = tmp;
if (family == OW_FAMILY_TEMP3) { // AD: DS18S20
tmp = scratch[0];
if (scratch[1]) tmp = tmp * -1;
// For the DS18S20, use COUNT_REMAIN to calculate 12 bit value
devreadout[i] = ((tmp & 0xFFFE) << 3) +12 - scratch[6]; // 6:COUNT_REMAIN
//printf("%s: [%d] read: %d(%d), devreadout: %d, COUNT_REMAIN: %d Scratchpad: %02x %02x %02x %02x %02x %02x %02x %02x\n", __FUNCTION__, i, tmp, numBytesToRead,devreadout[i], scratch[6],
// scratch[0],scratch[1],scratch[2],scratch[3],scratch[4],scratch[5],scratch[6],scratch[7]);
} else {
tmp = scratch[1]<<8 | scratch[0];
devreadout[i] = tmp;
tmp = scratch[3]<<8 | scratch[2];
extrareadout[i] = tmp;
}
}
mystate = 0;
} else {
Expand Down