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Diffstat (limited to 'libraries/Wire/src/utility/twi.c')
-rw-r--r--libraries/Wire/src/utility/twi.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/libraries/Wire/src/utility/twi.c b/libraries/Wire/src/utility/twi.c
index 7efcc5a..171af73 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
@@ -288,7 +304,7 @@ uint8_t twi_transmit(const uint8_t* data, uint8_t length)
uint8_t i;
// ensure data will fit into buffer
- if(TWI_BUFFER_LENGTH < length){
+ if(TWI_BUFFER_LENGTH < (twi_txBufferLength+length)){
return 1;
}
@@ -298,10 +314,10 @@ uint8_t twi_transmit(const uint8_t* data, uint8_t length)
}
// set length and copy data into tx buffer
- twi_txBufferLength = length;
for(i = 0; i < length; ++i){
- twi_txBuffer[i] = data[i];
+ twi_txBuffer[twi_txBufferLength+i] = data[i];
}
+ twi_txBufferLength += length;
return 0;
}