two way serial test.

serial/loop-data.c

@@ -0,0 +1,56 @@
+#include <pic14\pic16f876.h>
+#include <stdint.h> //Needed for uint16_t
+
+// last one works and puts it in ASM file
+static __code uint16_t __at (0x2007) config = _XT_OSC & _PWRTE_ON & _BODEN_ON & _CP_OFF & _LVP_OFF & _WDT_OFF;
+
+
+// If KHZ is not specified by the makefile, assume it to be 4 MHZ
+#ifndef KHZ
+#define KHZ 4000
+#endif
+
+// These are fixed. The 16f876 can only use these as transmit and recieve.
+#define TX_PORT 6
+#define RX_PORT 7
+#define TX_BIT (1<<TX_PORT)
+#define RX_BIT (1<<RX_PORT)
+
+
+// Twiddle these as you like BUT remember that not all values work right!
+// See the datasheet for what values can work with what clock frequencies.
+#define BAUD 9600
+#define BAUD_HI 1
+
+// This section calculate!s the proper value for SPBRG from the given
+// values of BAUD and BAUD_HI. Derived from Microchip's datasheet.
+#if (BAUD_HI == 1)
+#define BAUD_FACTOR (16L*BAUD)
+#else
+#define BAUD_FACTOR (64L*BAUD)
+#endif
+#define SPBRG_VALUE (unsigned char)(((KHZ*1000L)-BAUD_FACTOR)/BAUD_FACTOR)
+
+void main(void)
+{
+ static unsigned char i;
+
+ TRISB=TX_BIT|RX_BIT; // These need to be 1 for USART to work
+
+ SPBRG=SPBRG_VALUE; // Baud Rate register, calculated by macro
+ BRGH=BAUD_HI;
+
+ SYNC=0; // Disable Synchronous/Enable Asynchronous
+ SPEN=1; // Enable serial port
+ TXEN=1; // Enable transmission mode
+ CREN=1; // Enable reception mode
+
+ while(1)
+ {
+ while(!RCIF); // Wait until data recieved
+ i=RCREG; // Store for later
+
+ while(!TRMT); // Wait until we're free to transmit
+ TXREG=i; // Transmit
+ }
+}