diff options
| -rw-r--r-- | libraries/Wire/src/Wire.cpp | 4 | ||||
| -rw-r--r-- | libraries/Wire/src/utility/twi.c | 16 | ||||
| -rw-r--r-- | libraries/Wire/src/utility/twi.h | 1 |
3 files changed, 19 insertions, 2 deletions
diff --git a/libraries/Wire/src/Wire.cpp b/libraries/Wire/src/Wire.cpp index 86696e9..d2146f7 100644 --- a/libraries/Wire/src/Wire.cpp +++ b/libraries/Wire/src/Wire.cpp @@ -80,9 +80,9 @@ void TwoWire::end(void) twi_disable(); } -void TwoWire::setClock(uint32_t frequency) +void TwoWire::setClock(uint32_t clock) { - TWBR = ((F_CPU / frequency) - 16) / 2; + twi_setFrequency(clock); } uint8_t TwoWire::requestFrom(uint8_t address, uint8_t quantity, uint32_t iaddress, uint8_t isize, uint8_t sendStop) diff --git a/libraries/Wire/src/utility/twi.c b/libraries/Wire/src/utility/twi.c index 7efcc5a..f5d7d5b 100644 --- a/libraries/Wire/src/utility/twi.c +++ b/libraries/Wire/src/utility/twi.c @@ -119,6 +119,22 @@ void twi_setAddress(uint8_t address) } /* + * Function twi_setClock + * Desc sets twi bit rate + * Input Clock Frequency + * Output none + */ +void twi_setFrequency(uint32_t frequency) +{ + TWBR = ((F_CPU / frequency) - 16) / 2; + + /* twi bit rate formula from atmega128 manual pg 204 + SCL Frequency = CPU Clock Frequency / (16 + (2 * TWBR)) + note: TWBR should be 10 or higher for master mode + It is 72 for a 16mhz Wiring board with 100kHz TWI */ +} + +/* * Function twi_readFrom * Desc attempts to become twi bus master and read a * series of bytes from a device on the bus diff --git a/libraries/Wire/src/utility/twi.h b/libraries/Wire/src/utility/twi.h index 4c52bc5..d27325e 100644 --- a/libraries/Wire/src/utility/twi.h +++ b/libraries/Wire/src/utility/twi.h @@ -41,6 +41,7 @@ void twi_init(void); void twi_disable(void); void twi_setAddress(uint8_t); + void twi_setFrequency(uint32_t); uint8_t twi_readFrom(uint8_t, uint8_t*, uint8_t, uint8_t); uint8_t twi_writeTo(uint8_t, uint8_t*, uint8_t, uint8_t, uint8_t); uint8_t twi_transmit(const uint8_t*, uint8_t); |