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-rwxr-xr-xkeyboards/meira/TWIlib.c287
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diff --git a/keyboards/meira/TWIlib.c b/keyboards/meira/TWIlib.c
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+/*
+ * TWIlib.c
+ *
+ * Created: 6/01/2014 10:41:33 PM
+ * Author: Chris Herring
+ */
+
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include "TWIlib.h"
+#include "util/delay.h"
+#include "print.h"
+
+void TWIInit()
+{
+ TWIInfo.mode = Ready;
+ TWIInfo.errorCode = 0xFF;
+ TWIInfo.repStart = 0;
+ // Set pre-scalers (no pre-scaling)
+ TWSR = 0;
+ // Set bit rate
+ TWBR = ((F_CPU / TWI_FREQ) - 16) / 2;
+ // Enable TWI and interrupt
+ TWCR = (1 << TWIE) | (1 << TWEN);
+}
+
+uint8_t isTWIReady()
+{
+ if ( (TWIInfo.mode == Ready) | (TWIInfo.mode == RepeatedStartSent) )
+ {
+
+// xprintf("i2c ready\n");
+ return 1;
+ }
+ else
+ {
+ if(TWIInfo.mode == Initializing){
+ switch(TWIInfo.errorCode){
+ case TWI_SUCCESS:
+ break;
+ case TWI_NO_RELEVANT_INFO:
+
+ break;
+ case TWI_LOST_ARBIT:
+ case TWI_MT_DATA_NACK:
+ // Some kind of I2C error, reset and re-init
+ xprintf("I2C init error: %d\n", TWIInfo.errorCode);
+ TWCR = (1 << TWINT)|(1 << TWSTO);
+ TWIInit();
+ break;
+ default:
+ xprintf("Other i2c init error: %d\n", TWIInfo.errorCode);
+ }
+ }
+ return 0;
+ }
+}
+
+
+void TWITransmitData(void *const TXdata, uint8_t dataLen, uint8_t repStart, uint8_t blocking)
+{
+ // Wait until ready
+ while (!isTWIReady()) {_delay_us(1);}
+ // Reset the I2C stuff
+ TWCR = (1 << TWINT)|(1 << TWSTO);
+ TWIInit();
+ // Set repeated start mode
+ TWIInfo.repStart = repStart;
+ // Copy transmit info to global variables
+ TWITransmitBuffer = (uint8_t *)TXdata;
+ TXBuffLen = dataLen;
+ TXBuffIndex = 0;
+
+ // If a repeated start has been sent, then devices are already listening for an address
+ // and another start does not need to be sent.
+ if (TWIInfo.mode == RepeatedStartSent)
+ {
+ TWIInfo.mode = Initializing;
+ TWDR = TWITransmitBuffer[TXBuffIndex++]; // Load data to transmit buffer
+ TWISendTransmit(); // Send the data
+ }
+ else // Otherwise, just send the normal start signal to begin transmission.
+ {
+ TWIInfo.mode = Initializing;
+ TWISendStart();
+ }
+ if(blocking){
+ // Wait until ready
+ while (!isTWIReady()){_delay_us(1);}
+ }
+}
+
+
+// uint8_t TWITransmitData(void *const TXdata, uint8_t dataLen, uint8_t repStart)
+// {
+// if (dataLen <= TXMAXBUFLEN)
+// {
+// // Wait until ready
+// while (!isTWIReady()) {_delay_us(1);}
+// // Set repeated start mode
+// TWIInfo.repStart = repStart;
+// // Copy data into the transmit buffer
+// uint8_t *data = (uint8_t *)TXdata;
+// for (int i = 0; i < dataLen; i++)
+// {
+// TWITransmitBuffer[i] = data[i];
+// }
+// // Copy transmit info to global variables
+// TXBuffLen = dataLen;
+// TXBuffIndex = 0;
+
+// // If a repeated start has been sent, then devices are already listening for an address
+// // and another start does not need to be sent.
+// if (TWIInfo.mode == RepeatedStartSent)
+// {
+// TWIInfo.mode = Initializing;
+// TWDR = TWITransmitBuffer[TXBuffIndex++]; // Load data to transmit buffer
+// TWISendTransmit(); // Send the data
+// }
+// else // Otherwise, just send the normal start signal to begin transmission.
+// {
+// TWIInfo.mode = Initializing;
+// TWISendStart();
+// }
+
+// }
+// else
+// {
+// return 1; // return an error if data length is longer than buffer
+// }
+// return 0;
+// }
+
+uint8_t TWIReadData(uint8_t TWIaddr, uint8_t bytesToRead, uint8_t repStart)
+{
+ // Check if number of bytes to read can fit in the RXbuffer
+ if (bytesToRead < RXMAXBUFLEN)
+ {
+ // Reset buffer index and set RXBuffLen to the number of bytes to read
+ RXBuffIndex = 0;
+ RXBuffLen = bytesToRead;
+ // Create the one value array for the address to be transmitted
+ uint8_t TXdata[1];
+ // Shift the address and AND a 1 into the read write bit (set to write mode)
+ TXdata[0] = (TWIaddr << 1) | 0x01;
+ // Use the TWITransmitData function to initialize the transfer and address the slave
+ TWITransmitData(TXdata, 1, repStart, 0);
+ }
+ else
+ {
+ return 0;
+ }
+ return 1;
+}
+
+ISR (TWI_vect)
+{
+ switch (TWI_STATUS)
+ {
+ // ----\/ ---- MASTER TRANSMITTER OR WRITING ADDRESS ----\/ ---- //
+ case TWI_MT_SLAW_ACK: // SLA+W transmitted and ACK received
+ // Set mode to Master Transmitter
+ TWIInfo.mode = MasterTransmitter;
+ case TWI_START_SENT: // Start condition has been transmitted
+ case TWI_MT_DATA_ACK: // Data byte has been transmitted, ACK received
+ if (TXBuffIndex < TXBuffLen) // If there is more data to send
+ {
+ TWDR = TWITransmitBuffer[TXBuffIndex++]; // Load data to transmit buffer
+ TWIInfo.errorCode = TWI_NO_RELEVANT_INFO;
+ TWISendTransmit(); // Send the data
+ }
+ // This transmission is complete however do not release bus yet
+ else if (TWIInfo.repStart)
+ {
+ TWIInfo.errorCode = 0xFF;
+ TWISendStart();
+ }
+ // All transmissions are complete, exit
+ else
+ {
+ TWIInfo.mode = Ready;
+ TWIInfo.errorCode = 0xFF;
+ TWISendStop();
+ }
+ break;
+
+ // ----\/ ---- MASTER RECEIVER ----\/ ---- //
+
+ case TWI_MR_SLAR_ACK: // SLA+R has been transmitted, ACK has been received
+ // Switch to Master Receiver mode
+ TWIInfo.mode = MasterReceiver;
+ // If there is more than one byte to be read, receive data byte and return an ACK
+ if (RXBuffIndex < RXBuffLen-1)
+ {
+ TWIInfo.errorCode = TWI_NO_RELEVANT_INFO;
+ TWISendACK();
+ }
+ // Otherwise when a data byte (the only data byte) is received, return NACK
+ else
+ {
+ TWIInfo.errorCode = TWI_NO_RELEVANT_INFO;
+ TWISendNACK();
+ }
+ break;
+
+ case TWI_MR_DATA_ACK: // Data has been received, ACK has been transmitted.
+
+ /// -- HANDLE DATA BYTE --- ///
+ TWIReceiveBuffer[RXBuffIndex++] = TWDR;
+ // If there is more than one byte to be read, receive data byte and return an ACK
+ if (RXBuffIndex < RXBuffLen-1)
+ {
+ TWIInfo.errorCode = TWI_NO_RELEVANT_INFO;
+ TWISendACK();
+ }
+ // Otherwise when a data byte (the only data byte) is received, return NACK
+ else
+ {
+ TWIInfo.errorCode = TWI_NO_RELEVANT_INFO;
+ TWISendNACK();
+ }
+ break;
+
+ case TWI_MR_DATA_NACK: // Data byte has been received, NACK has been transmitted. End of transmission.
+
+ /// -- HANDLE DATA BYTE --- ///
+ TWIReceiveBuffer[RXBuffIndex++] = TWDR;
+ // This transmission is complete however do not release bus yet
+ if (TWIInfo.repStart)
+ {
+ TWIInfo.errorCode = 0xFF;
+ TWISendStart();
+ }
+ // All transmissions are complete, exit
+ else
+ {
+ TWIInfo.mode = Ready;
+ TWIInfo.errorCode = 0xFF;
+ TWISendStop();
+ }
+ break;
+
+ // ----\/ ---- MT and MR common ----\/ ---- //
+
+ case TWI_MR_SLAR_NACK: // SLA+R transmitted, NACK received
+ case TWI_MT_SLAW_NACK: // SLA+W transmitted, NACK received
+ case TWI_MT_DATA_NACK: // Data byte has been transmitted, NACK received
+ case TWI_LOST_ARBIT: // Arbitration has been lost
+ // Return error and send stop and set mode to ready
+ if (TWIInfo.repStart)
+ {
+ TWIInfo.errorCode = TWI_STATUS;
+ TWISendStart();
+ }
+ // All transmissions are complete, exit
+ else
+ {
+ TWIInfo.mode = Ready;
+ TWIInfo.errorCode = TWI_STATUS;
+ TWISendStop();
+ }
+ break;
+ case TWI_REP_START_SENT: // Repeated start has been transmitted
+ // Set the mode but DO NOT clear TWINT as the next data is not yet ready
+ TWIInfo.mode = RepeatedStartSent;
+ break;
+
+ // ----\/ ---- SLAVE RECEIVER ----\/ ---- //
+
+ // TODO IMPLEMENT SLAVE RECEIVER FUNCTIONALITY
+
+ // ----\/ ---- SLAVE TRANSMITTER ----\/ ---- //
+
+ // TODO IMPLEMENT SLAVE TRANSMITTER FUNCTIONALITY
+
+ // ----\/ ---- MISCELLANEOUS STATES ----\/ ---- //
+ case TWI_NO_RELEVANT_INFO: // It is not really possible to get into this ISR on this condition
+ // Rather, it is there to be manually set between operations
+ break;
+ case TWI_ILLEGAL_START_STOP: // Illegal START/STOP, abort and return error
+ TWIInfo.errorCode = TWI_ILLEGAL_START_STOP;
+ TWIInfo.mode = Ready;
+ TWISendStop();
+ break;
+ }
+
+}
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