mirror of
https://github.com/openstenoproject/qmk
synced 2024-11-15 04:54:43 +00:00
296 lines
8.1 KiB
C
296 lines
8.1 KiB
C
/*
|
|
* 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"
|
|
|
|
// Global transmit buffer
|
|
volatile uint8_t *TWITransmitBuffer;
|
|
// Global receive buffer
|
|
volatile uint8_t TWIReceiveBuffer[RXMAXBUFLEN];
|
|
// Buffer indexes
|
|
volatile int TXBuffIndex; // Index of the transmit buffer. Is volatile, can change at any time.
|
|
int RXBuffIndex; // Current index in the receive buffer
|
|
// Buffer lengths
|
|
int TXBuffLen; // The total length of the transmit buffer
|
|
int RXBuffLen; // The total number of bytes to read (should be less than RXMAXBUFFLEN)
|
|
|
|
TWIInfoStruct TWIInfo;
|
|
|
|
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) )
|
|
{
|
|
return 1;
|
|
}
|
|
else
|
|
{
|
|
if(TWIInfo.mode == Initializing){
|
|
switch(TWIInfo.errorCode){
|
|
case TWI_SUCCESS:
|
|
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;
|
|
}
|
|
|
|
}
|