Switch software UART over to timer 1 and remove timer prescaling to try to prevent...

[pub/USBasp.git] / Projects / XPLAINBridge / Lib / SoftUART.c

diff --git a/Projects/XPLAINBridge/Lib/SoftUART.c b/Projects/XPLAINBridge/Lib/SoftUART.c
index 0591284..c001c07 100644 (file)
--- a/Projects/XPLAINBridge/Lib/SoftUART.c
+++ b/Projects/XPLAINBridge/Lib/SoftUART.c
@@ -44,10 +44,10 @@ static uint8_t RX_BitMask, RX_Data;
 
 void SoftUART_Init(void)
 {
 
 void SoftUART_Init(void)
 {

-       OCR2B  = TCNT2 + 1;                                             // force first compare
-       TCCR2A = (1 << COM2B1) | (1 << COM2B0); // T1 mode 0
-       TCCR2B = (1 << FOC2B)  | (1 << CS21);   // CLK/8, T1 mode 0
-       TIMSK2 = (1 << OCIE2B);                                 // enable tx and wait for start
+       OCR1B  = TCNT1 + 1;                                             // force first compare
+       TCCR1B = (1 << CS10);                                   // CLK/1, T1 mode 0
+       TCCR1C = (1 << FOC1B);
+       TIMSK1 = (1 << OCIE1B);                                 // enable tx and wait for start

        EICRA  = (1 << ISC01);                                  // -ve edge
        EIMSK  = (1 << INT0);                                   // enable INT0 interrupt
 
        EICRA  = (1 << ISC01);                                  // -ve edge
        EIMSK  = (1 << INT0);                                   // enable INT0 interrupt
 


@@ -59,22 +59,22 @@ void SoftUART_Init(void)
 /* ISR to detect the start of a bit being sent to the software UART. */
 ISR(INT0_vect)
 {
 /* ISR to detect the start of a bit being sent to the software UART. */
 ISR(INT0_vect)
 {

-       OCR2A = TCNT2 + (uint16_t)((BIT_TIME / 8.0f) * 1.5f);   // scan 1.5 bits after start
+       OCR1A = TCNT1 + ((BIT_TIME * 3) / 2) - 1;       // scan 1.5 bits after start

 
        RX_Data    = 0;                                                 // clear bit storage
        RX_BitMask = (1 << 0);                                  // bit mask
 
 
        RX_Data    = 0;                                                 // clear bit storage
        RX_BitMask = (1 << 0);                                  // bit mask
 

-       TIFR2 = (1 << OCF2A);                                   // clear pending interrupt
+       TIFR1 = (1 << OCF1A);                                   // clear pending interrupt

 
        if (!(SRXPIN & (1 << SRX)))                             // still low
        {
 
        if (!(SRXPIN & (1 << SRX)))                             // still low
        {

-               TIMSK2 =  (1 << OCIE2A) | (1 << OCIE2B); // wait for first bit
+               TIMSK1 =  (1 << OCIE1A) | (1 << OCIE1B); // wait for first bit

                EIMSK &= ~(1 << INT0);
        }
 }
 
 /* ISR to manage the reception of bits to the software UART. */
                EIMSK &= ~(1 << INT0);
        }
 }
 
 /* ISR to manage the reception of bits to the software UART. */

-ISR(TIMER2_COMPA_vect)
+ISR(TIMER1_COMPA_vect)

 {
        if (RX_BitMask)
        {
 {
        if (RX_BitMask)
        {


@@ -83,37 +83,37 @@ ISR(TIMER2_COMPA_vect)
 
                RX_BitMask <<= 1;
 
 
                RX_BitMask <<= 1;
 

-               OCR2A += BIT_TIME / 8;                          // next bit slice
+               OCR1A += BIT_TIME;                              // next bit slice

        }
        else
        {
                RingBuffer_Insert(&UARTtoUSB_Buffer, RX_Data);
 
        }
        else
        {
                RingBuffer_Insert(&UARTtoUSB_Buffer, RX_Data);
 

-               TIMSK2  = (1 << OCIE2B);                        // enable tx and wait for start
+               TIMSK1  = (1 << OCIE1B);                        // enable tx and wait for start

                EIMSK  |= (1 << INT0);                          // enable START irq
                EIFR    = (1 << INTF0);                         // clear any pending
        }
 }
 
 /* ISR to manage the transmission of bits via the software UART. */
                EIMSK  |= (1 << INT0);                          // enable START irq
                EIFR    = (1 << INTF0);                         // clear any pending
        }
 }
 
 /* ISR to manage the transmission of bits via the software UART. */

-ISR(TIMER2_COMPB_vect)
+ISR(TIMER1_COMPB_vect)

 {
 {

-       OCR2B += BIT_TIME / 8;                                  // next bit slice
+       OCR1B += BIT_TIME;                                      // next bit slice

 
        if (TX_BitsRemaining)
        {
                if (--TX_BitsRemaining != 9)            // no start bit
                {
                        if (TX_Data & (1 << 0))                 // test inverted data
 
        if (TX_BitsRemaining)
        {
                if (--TX_BitsRemaining != 9)            // no start bit
                {
                        if (TX_Data & (1 << 0))                 // test inverted data

-                         TCCR2A = (1 << COM2B1);
+                         STXPORT &= ~(1 << STX);

                        else
                        else

-                         TCCR2A = (1 << COM2B1) | (1 << COM2B0);
+                         STXPORT =   (1 << STX);

 
                        TX_Data >>= 1;                                  // shift zero in from left
                }
                else
                {
 
                        TX_Data >>= 1;                                  // shift zero in from left
                }
                else
                {

-                       TCCR2A = (1 << COM2B1);                 // START bit
+                       STXPORT &= ~(1 << STX);

                }
        }
        else if (USBtoUART_Buffer.Count)
                }
        }
        else if (USBtoUART_Buffer.Count)