Rename software USART driver globals to make the code more in line with the rest...

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

diff --git a/Projects/XPLAINBridge/Lib/SoftUART.c b/Projects/XPLAINBridge/Lib/SoftUART.c
index 5e589f3..0591284 100644 (file)
--- a/Projects/XPLAINBridge/Lib/SoftUART.c
+++ b/Projects/XPLAINBridge/Lib/SoftUART.c
@@ -30,27 +30,17 @@
   this software.
 */
 
-#include "SoftUART.h"
-
-volatile bool    srx_done;
-volatile uint8_t stx_count;
-static   uint8_t srx_data, srx_mask, srx_tmp, stx_data;
-
-void SoftUART_TxByte(uint8_t Byte)
-{
-       while (stx_count);
+/** \file
+ *
+ *  Software UART for both data transmission and reception. This
+ *  code continuously monitors the ring buffers set up by the main
+ *  project source file and reads/writes data as it becomes available.
+ */
 
-       stx_data  = ~Byte;
-       stx_count = 10;
-}
-
-uint8_t SoftUART_RxByte(void)
-{
-       while (!(srx_done));
-       srx_done = false;
+#include "SoftUART.h"
 
-       return srx_data;
-}
+static uint8_t TX_BitsRemaining, TX_Data;
+static uint8_t RX_BitMask, RX_Data;
 
 void SoftUART_Init(void)
 {
@@ -61,71 +51,74 @@ void SoftUART_Init(void)
        EICRA  = (1 << ISC01);                                  // -ve edge
        EIMSK  = (1 << INT0);                                   // enable INT0 interrupt
 
-       stx_count = 0;                                                  // nothing to send
-       srx_done  = false;                                              // nothing received
        STXPORT |= (1 << STX);                                  // TX output
        STXDDR  |= (1 << STX);                                  // TX output
        SRXPORT |= (1 << SRX);                                  // pullup on INT0
 }
 
-/* ISR to detect the start of a bit being sent from the transmitter. */
+/* ISR to detect the start of a bit being sent to the software UART. */
 ISR(INT0_vect)
 {
-       OCR2A = TCNT2 + (BIT_TIME / 8 * 3 / 2); // scan 1.5 bits after start
+       OCR2A = TCNT2 + (uint16_t)((BIT_TIME / 8.0f) * 1.5f);   // scan 1.5 bits after start
 
-       srx_tmp  = 0;                                                   // clear bit storage
-       srx_mask = 1;                                                   // bit mask
+       RX_Data    = 0;                                                 // clear bit storage
+       RX_BitMask = (1 << 0);                                  // bit mask
 
        TIFR2 = (1 << OCF2A);                                   // clear pending interrupt
 
        if (!(SRXPIN & (1 << SRX)))                             // still low
        {
-               TIMSK2 = (1 << OCIE2A) | (1 << OCIE2B); // wait for first bit
+               TIMSK2 =  (1 << OCIE2A) | (1 << OCIE2B); // wait for first bit
                EIMSK &= ~(1 << INT0);
        }
 }
 
-/* ISR to manage the reception of bits to the transmitter. */
+/* ISR to manage the reception of bits to the software UART. */
 ISR(TIMER2_COMPA_vect)
 {
-       if (srx_mask)
+       if (RX_BitMask)
        {
                if (SRXPIN & (1 << SRX))
-                 srx_tmp |= srx_mask;
+                 RX_Data |= RX_BitMask;
 
-               srx_mask <<= 1;
+               RX_BitMask <<= 1;
 
                OCR2A += BIT_TIME / 8;                          // next bit slice
        }
        else
        {
-               srx_done  = true;                                       // mark rx data valid
-               srx_data  = srx_tmp;                            // store rx data
-               TIMSK2    = (1 << OCIE2B);                      // enable tx and wait for start
-               EIMSK    |= (1 << INT0);                        // enable START irq
-               EIFR      = (1 << INTF0);                       // clear any pending
+               RingBuffer_Insert(&UARTtoUSB_Buffer, RX_Data);
+
+               TIMSK2  = (1 << OCIE2B);                        // 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 to the receiver. */
+/* ISR to manage the transmission of bits via the software UART. */
 ISR(TIMER2_COMPB_vect)
 {
        OCR2B += BIT_TIME / 8;                                  // next bit slice
 
-       if (stx_count)
+       if (TX_BitsRemaining)
        {
-               if (--stx_count != 9)                           // no start bit
+               if (--TX_BitsRemaining != 9)            // no start bit
                {
-                       if (!(stx_data & 1))                    // test inverted data
-                         TCCR2A = (1 << COM2B1) | (1 << COM2B0);
-                       else
+                       if (TX_Data & (1 << 0))                 // test inverted data
                          TCCR2A = (1 << COM2B1);
+                       else
+                         TCCR2A = (1 << COM2B1) | (1 << COM2B0);
 
-                       stx_data >>= 1;                                 // shift zero in from left
+                       TX_Data >>= 1;                                  // shift zero in from left
                }
                else
                {
                        TCCR2A = (1 << COM2B1);                 // START bit
                }
        }
+       else if (USBtoUART_Buffer.Count)
+       {
+               TX_Data = ~RingBuffer_Remove(&USBtoUART_Buffer);
+               TX_BitsRemaining = 10;
+       }
 }