X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/5a4def747897c1c6ffbe465506d846c7c686d3e9..e39f3378a21ae5076e8c49bc728c20e436e3a69f:/Projects/XPLAINBridge/Lib/SoftUART.c?ds=sidebyside diff --git a/Projects/XPLAINBridge/Lib/SoftUART.c b/Projects/XPLAINBridge/Lib/SoftUART.c index 00bb38320..152c4e187 100644 --- a/Projects/XPLAINBridge/Lib/SoftUART.c +++ b/Projects/XPLAINBridge/Lib/SoftUART.c @@ -1,15 +1,15 @@ /* - LUFA Library - Copyright (C) Dean Camera, 2010. + LUFA Library + Copyright (C) Dean Camera, 2012. dean [at] fourwalledcubicle [dot] com - www.fourwalledcubicle.com + www.lufa-lib.org */ /* Copyright 2010 David Prentice (david.prentice [at] farming [dot] uk) Copyright 2010 Peter Danneger - Copyright 2010 Dean Camera (dean [at] fourwalledcubicle [dot] com) + Copyright 2012 Dean Camera (dean [at] fourwalledcubicle [dot] com) Permission to use, copy, modify, distribute, and sell this software and its documentation for any purpose is hereby granted @@ -51,7 +51,8 @@ static uint8_t RX_BitsRemaining; /** Temporary data variable to hold the byte being received as it is shifted in */ static uint8_t RX_Data; -/** Initialises the software UART, ready for data transmission and reception into the global ring buffers. */ + +/** Initializes the software UART, ready for data transmission and reception into the global ring buffers. */ void SoftUART_Init(void) { /* Set TX pin to output high, enable RX pull-up */ @@ -67,11 +68,11 @@ void SoftUART_Init(void) SoftUART_SetBaud(9600); /* Setup reception timer compare ISR */ - TIMSK1 = (1 << ICIE1); + TIMSK1 = (1 << OCIE1A); /* Setup transmission timer compare ISR and start the timer */ - TIMSK3 = (1 << ICIE3); - TCCR3B = ((1 << CS30) | (1 << WGM33) | (1 << WGM32)); + TIMSK3 = (1 << OCIE3A); + TCCR3B = ((1 << CS30) | (1 << WGM32)); } /** ISR to detect the start of a bit being sent to the software UART. */ @@ -80,8 +81,10 @@ ISR(INT0_vect, ISR_BLOCK) /* Reset the number of reception bits remaining counter */ RX_BitsRemaining = 8; - /* Reset the bit reception timer */ - TCNT1 = 0; + /* Reset the bit reception timer to -(1/2) of the total bit time, so that the first data bit is + * sampled mid way through the total bit time, making reception more robust. + */ + TCNT1 = -(OCR1A >> 1); /* Check to see that the pin is still low (prevents glitches from starting a frame reception) */ if (!(SRXPIN & (1 << SRX))) @@ -90,12 +93,12 @@ ISR(INT0_vect, ISR_BLOCK) EIMSK = 0; /* Start the reception timer */ - TCCR1B = ((1 << CS10) | (1 << WGM13) | (1 << WGM12)); + TCCR1B = ((1 << CS10) | (1 << WGM12)); } } /** ISR to manage the reception of bits to the software UART. */ -ISR(TIMER1_CAPT_vect, ISR_BLOCK) +ISR(TIMER1_COMPA_vect, ISR_BLOCK) { /* Cache the current RX pin value for later checking */ uint8_t SRX_Cached = (SRXPIN & (1 << SRX)); @@ -120,12 +123,12 @@ ISR(TIMER1_CAPT_vect, ISR_BLOCK) /* Reception complete, store the received byte if stop bit valid */ if (SRX_Cached) - RingBuffer_Insert(&XMEGAtoUSB_Buffer, RX_Data); + RingBuffer_Insert(&UARTtoUSB_Buffer, RX_Data); } } /** ISR to manage the transmission of bits via the software UART. */ -ISR(TIMER3_CAPT_vect, ISR_BLOCK) +ISR(TIMER3_COMPA_vect, ISR_BLOCK) { /* Check if transmission has finished */ if (TX_BitsRemaining) @@ -140,13 +143,13 @@ ISR(TIMER3_CAPT_vect, ISR_BLOCK) TX_Data >>= 1; TX_BitsRemaining--; } - else if (!(RX_BitsRemaining) && !(RingBuffer_IsEmpty(&USBtoXMEGA_Buffer))) + else if (!(RX_BitsRemaining) && !(RingBuffer_IsEmpty(&USBtoUART_Buffer))) { /* Start bit - TX line low */ STXPORT &= ~(1 << STX); /* Transmission complete, get the next byte to send (if available) */ - TX_Data = ~RingBuffer_Remove(&USBtoXMEGA_Buffer); + TX_Data = ~RingBuffer_Remove(&USBtoUART_Buffer); TX_BitsRemaining = 9; } }