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Apply power selection at the end of the write slot while IRQs are masked (#1808)

This commit is contained in:
Arnim Läuger 2017-03-01 12:41:17 +01:00 committed by Marcel Stör
parent 5feae3fee1
commit 2168e5185e
2 changed files with 25 additions and 21 deletions
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44
app/driver/onewire.c
View File

@ -122,15 +122,29 @@ uint8_t onewire_reset(uint8_t pin)
// Write a bit. Port and bit is used to cut lookup time and provide
// more certain timing.
//
static void onewire_write_bit(uint8_t pin, uint8_t v)
static void onewire_write_bit(uint8_t pin, uint8_t v, uint8_t power)
{
if (v & 1) {
onewire_read_bit(pin);
noInterrupts();
DIRECT_WRITE_LOW(pin);
delayMicroseconds(5);
if (power) {
DIRECT_WRITE_HIGH(pin);
} else {
DIRECT_MODE_INPUT(pin); // drive output high by the pull-up
}
delayMicroseconds(8);
interrupts();
delayMicroseconds(52);
} else {
noInterrupts();
DIRECT_WRITE_LOW(pin);
delayMicroseconds(65);
DIRECT_MODE_INPUT(pin); // drive output high by the pull-up
if (power) {
DIRECT_WRITE_HIGH(pin);
} else {
DIRECT_MODE_INPUT(pin); // drive output high by the pull-up
}
interrupts();
delayMicroseconds(5);
}
@ -157,9 +171,10 @@ static uint8_t onewire_read_bit(uint8_t pin)
}
//
// Write a byte. The writing code uses the active drivers to raise the
// Write a byte. The writing code uses the external pull-up to raise the
// pin high, if you need power after the write (e.g. DS18S20 in
// parasite power mode) then set 'power' to 1, otherwise the pin will
// parasite power mode) then set 'power' to 1 and the output driver will
// be activated at the end of the write. Otherwise the pin will
// go tri-state at the end of the write to avoid heating in a short or
// other mishap.
//
@ -167,26 +182,15 @@ void onewire_write(uint8_t pin, uint8_t v, uint8_t power /* = 0 */) {
uint8_t bitMask;
for (bitMask = 0x01; bitMask; bitMask <<= 1) {
onewire_write_bit(pin, (bitMask & v)?1:0);
}
if ( power ) {
noInterrupts();
DIRECT_WRITE_HIGH(pin);
interrupts();
// send last bit with requested power mode
onewire_write_bit(pin, (bitMask & v)?1:0, bitMask & 0x80 ? power : 0);
}
}
void onewire_write_bytes(uint8_t pin, const uint8_t *buf, uint16_t count, bool power /* = 0 */) {
uint16_t i;
for (i = 0 ; i < count ; i++)
onewire_write(pin, buf[i], owDefaultPower);
if ( power ) {
noInterrupts();
DIRECT_WRITE_HIGH(pin);
interrupts();
}
onewire_write(pin, buf[i], i < count-1 ? owDefaultPower : power);
}
//
@ -360,7 +364,7 @@ uint8_t onewire_search(uint8_t pin, uint8_t *newAddr)
ROM_NO[pin][rom_byte_number] &= ~rom_byte_mask;
// serial number search direction write bit
onewire_write_bit(pin, search_direction);
onewire_write_bit(pin, search_direction, 0);
// increment the byte counter id_bit_number
// and shift the mask rom_byte_mask

2
app/include/driver/onewire.h
View File

@ -74,7 +74,7 @@ void onewire_read_bytes(uint8_t pin, uint8_t *buf, uint16_t count);
// Write a bit. The bus is always left powered at the end, see
// note in write() about that.
static void onewire_write_bit(uint8_t pin, uint8_t v);
static void onewire_write_bit(uint8_t pin, uint8_t v, uint8_t power);
// Read a bit.
static uint8_t onewire_read_bit(uint8_t pin);