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I2CManager_Mega4809.h - allow other I2C clock speeds.

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This commit is contained in:
Neil McKechnie 2023-01-24 09:35:10 +00:00
parent a3d4255fee
commit d0ce59b19f
1 changed files with 23 additions and 25 deletions
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48
I2CManager_Mega4809.h
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@ -1,5 +1,5 @@
/*
* © 2021, Neil McKechnie. All rights reserved.
* © 2023, Neil McKechnie. All rights reserved.
*
* This file is part of CommandStation-EX
*
@ -28,21 +28,21 @@
***************************************************************************/
void I2CManagerClass::I2C_setClock(unsigned long i2cClockSpeed) {
uint16_t t_rise;
if (i2cClockSpeed < 200000) {
i2cClockSpeed = 100000;
if (i2cClockSpeed < 200000)
t_rise = 1000;
} else if (i2cClockSpeed < 800000) {
i2cClockSpeed = 400000;
else if (i2cClockSpeed < 800000)
t_rise = 300;
} else if (i2cClockSpeed < 1200000) {
i2cClockSpeed = 1000000;
else
t_rise = 120;
} else {
i2cClockSpeed = 100000;
t_rise = 1000;
}
if (t_rise == 120)
TWI0.CTRLA |= TWI_FMPEN_bm;
else
TWI0.CTRLA &= ~TWI_FMPEN_bm;
uint32_t baud = (F_CPU_CORRECTED / i2cClockSpeed - F_CPU_CORRECTED / 1000 / 1000
* t_rise / 1000 - 10) / 2;
if (baud > 255) baud = 255; // ~30kHz
TWI0.MBAUD = (uint8_t)baud;
}
@ -54,13 +54,13 @@ void I2CManagerClass::I2C_init()
pinMode(PIN_WIRE_SDA, INPUT_PULLUP);
pinMode(PIN_WIRE_SCL, INPUT_PULLUP);
PORTMUX.TWISPIROUTEA |= TWI_MUX;
I2C_setClock(I2C_FREQ);
#if defined(I2C_USE_INTERRUPTS)
TWI0.MCTRLA = TWI_RIEN_bm | TWI_WIEN_bm | TWI_ENABLE_bm;
#else
TWI0.MCTRLA = TWI_ENABLE_bm;
#endif
I2C_setClock(I2C_FREQ);
TWI0.MSTATUS = TWI_BUSSTATE_IDLE_gc;
}
@ -70,6 +70,8 @@ void I2CManagerClass::I2C_init()
void I2CManagerClass::I2C_sendStart() {
bytesToSend = currentRequest->writeLen;
bytesToReceive = currentRequest->readLen;
txCount = 0;
rxCount = 0;
// If anything to send, initiate write. Otherwise initiate read.
if (operation == OPERATION_READ || ((operation == OPERATION_REQUEST) && !bytesToSend))
@ -89,7 +91,10 @@ void I2CManagerClass::I2C_sendStop() {
* Close I2C down
***************************************************************************/
void I2CManagerClass::I2C_close() {
I2C_sendStop();
TWI0.MCTRLA &= ~(TWI_RIEN_bm | TWI_WIEN_bm | TWI_ENABLE_bm); // Switch off I2C
TWI0.MSTATUS = TWI_BUSSTATE_UNKNOWN_gc;
delayMicroseconds(10); // Wait for things to stabilise (hopefully)
}
/***************************************************************************
@ -114,15 +119,12 @@ void I2CManagerClass::I2C_handleInterrupt() {
TWI0.MCTRLB = TWI_MCMD_STOP_gc;
state = I2C_STATUS_NEGATIVE_ACKNOWLEDGE;
} else if (bytesToSend) {
// Acked, so send next byte
if (currentRequest->operation == OPERATION_SEND_P)
TWI0.MDATA = GETFLASH(currentRequest->writeBuffer + (txCount++));
else
TWI0.MDATA = currentRequest->writeBuffer[txCount++];
// Acked, so send next byte (don't need to use GETFLASH)
TWI0.MDATA = currentRequest->writeBuffer[txCount++];
bytesToSend--;
} else if (bytesToReceive) {
// Last sent byte acked and no more to send. Send repeated start, address and read bit.
TWI0.MADDR = (currentRequest->i2cAddress << 1) | 1;
// Last sent byte acked and no more to send. Send repeated start, address and read bit.
TWI0.MADDR = (currentRequest->i2cAddress << 1) | 1;
} else {
// No more data to send/receive. Initiate a STOP condition.
TWI0.MCTRLB = TWI_MCMD_STOP_gc;
@ -133,11 +135,7 @@ void I2CManagerClass::I2C_handleInterrupt() {
if (bytesToReceive) {
currentRequest->readBuffer[rxCount++] = TWI0.MDATA; // Store received byte
bytesToReceive--;
} else {
// Buffer full, issue nack/stop
TWI0.MCTRLB = TWI_ACKACT_bm | TWI_MCMD_STOP_gc;
state = I2C_STATUS_OK;
}
}
if (bytesToReceive) {
// More bytes to receive, issue ack and start another read
TWI0.MCTRLB = TWI_MCMD_RECVTRANS_gc;