PicBasic Pro program to demonstrate reading and writing the hardware serial port without HSERIN and HSEROUT. Defaults to 2400 bps.
' Name : USART.pbp ' Compiler : PICBASIC PRO Compiler 2.6 ' Assembler : PM or MPASM ' Target PIC : 16F, 18F with hardware USART ' Hardware : PC hardware serial port connection ' Oscillator : 4MHz external crystal or resonator ' Keywords : HARDWARE USART ' Description : PICBASIC PRO program to demonstrate reading & writing ' the hardware serial port without HSERIN/HSEROUT. Defaults to 2400 bps. ' B1 Var byte ' Initialize hardware USART TRISC = %10111111 ' Set TX (PortC.6) to out, rest in SPBRG = 25 ' Set baud rate to 2400 RCSTA = %10010000 ' Enable serial port and continuous receive TXSTA = %00100000 ' Enable transmit and asynchronous mode ' Echo received characters in infinite loop mainloop: Gosub charin ' Get a character from serial input, if any If B1 = 0 Then mainloop ' No character yet Gosub charout ' Send character to serial output Goto mainloop ' Do it forever ' Subroutine to get a character from USART receiver charin: B1 = 0 ' Preset to no character received If PIR1.5 = 1 Then ' If receive flag then... B1 = RCREG ' Get received character to B1 Endif Return ' Go back to caller ' Subroutine to send a character to USART transmitter charout: If PIR1.4 = 0 Then charout ' Wait for transmit register empty TXREG = B1 ' Send character to transmit register Return ' Go back to caller End