Commit 036a156f authored by Dean Camera's avatar Dean Camera
Browse files

Slight improvements to the reliability of the software UART in the XPLAINBridge project.

parent 931ca42a
......@@ -154,7 +154,7 @@ uint8_t CDC_Device_SendByte(USB_ClassInfo_CDC_Device_t* const CDCInterfaceInfo,
Endpoint_SelectEndpoint(CDCInterfaceInfo->Config.DataINEndpointNumber);
if (!(Endpoint_IsReadWriteAllowed()))
{
{
Endpoint_ClearIN();
uint8_t ErrorCode;
......
......@@ -63,41 +63,38 @@ void SoftUART_Init(void)
EICRA = (1 << ISC01);
EIMSK = (1 << INT0);
/* Ensure that when the timer is enabled the transmission ISR runs immediately */
OCR1B = TCNT1 + 1;
/* Start timer 1 with transmission channel force-enabled so that it will immediatly fire */
TCCR1C = (1 << FOC1B);
TIMSK1 = (1 << OCIE1B);
/* Start software UART transmission and reception timers */
TIMSK3 = (1 << OCIE3A);
TCCR3B = (1 << CS30);
TCCR1B = (1 << CS10);
}
/** ISR to detect the start of a bit being sent to the software UART. */
ISR(INT0_vect)
ISR(INT0_vect, ISR_BLOCK)
{
/* Set reception channel to fire 1.5 bits past the beginning of the start bit */
OCR1A = TCNT1 + ((BIT_TIME * 3) / 2);
OCR1A = TCNT1 + (BIT_TIME + (BIT_TIME / 2));
/* Clear the received data temporary variable, reset the current received bit position mask */
RX_Data = 0;
RX_BitMask = (1 << 0);
/* Clear reception channel ISR flag in case it is pending */
TIFR1 = (1 << OCF1A);
/* Check that the start bit is still low to prevent noise from triggering a reception */
if (!(SRXPIN & (1 << SRX)))
{
/* Still low, enable both send and receive channels */
TIMSK1 = (1 << OCIE1A) | (1 << OCIE1B);
/* Clear the start bit detection ISR flag if it is pending */
{
/* Clear reception channel ISR flag in case it is pending */
TIFR1 = (1 << OCF1A);
/* Still low, enable bit receive ISR */
TIMSK1 = (1 << OCIE1A);
/* Clear the start bit detection ISR flag */
EIMSK &= ~(1 << INT0);
}
}
/** ISR to manage the reception of bits to the software UART. */
ISR(TIMER1_COMPA_vect)
ISR(TIMER1_COMPA_vect, ISR_BLOCK)
{
/* Move the reception ISR compare position one bit ahead */
OCR1A += BIT_TIME;
......@@ -118,17 +115,17 @@ ISR(TIMER1_COMPA_vect)
RingBuffer_Insert(&UARTtoUSB_Buffer, RX_Data);
/* Disable the reception ISR as all data has now been received, re-enable start bit detection ISR */
TIMSK1 = (1 << OCIE1B);
EIMSK |= (1 << INT0);
EIFR = (1 << INTF0);
TIMSK1 = 0;
EIFR = (1 << INTF0);
EIMSK = (1 << INT0);
}
}
/** ISR to manage the transmission of bits via the software UART. */
ISR(TIMER1_COMPB_vect)
ISR(TIMER3_COMPA_vect, ISR_NOBLOCK)
{
/* Move the transmission ISR compare position one bit ahead */
OCR1B += BIT_TIME;
OCR3A += BIT_TIME;
/* Check if transmission has finished */
if (TX_BitsRemaining)
......
......@@ -151,7 +151,7 @@ void SetupHardware(void)
LEDs_Init();
USB_Init();
V2Protocol_Init();
/* Disable JTAG debugging */
MCUCR |= (1 << JTD);
MCUCR |= (1 << JTD);
......@@ -166,6 +166,8 @@ void SetupHardware(void)
/* Re-enable JTAG debugging */
MCUCR &= ~(1 << JTD);
MCUCR &= ~(1 << JTD);
CurrentFirmwareMode = MODE_USART_BRIDGE; // TEMP
}
/** Event handler for the library USB Configuration Changed event. */
......
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