Файл: Microcontroller Programming. Thi Micro Chip PIC (Julio Sanchez, 2007).pdf

;|______________________ CSRC Clock Source Select

;|_____________________ SPEN Serial Port Enable

;==============================

;transmit data ;==============================

;Test for Transmit Register Empty and transmit data in w SerialSend:

;==============================

;receive data ;==============================

;Procedure to test line for data received and return value

;in w. Overrun and framing errors are detected and

;remembered in the variable errorFlags, as follows:

;Bit 5 (RCIF) of the PIR1 Register is clear if the USART

;receive buffer is empty. If so, no data has been received

;At this point data has been received. First eliminate

;possible errors: overrun and framing.

;Bit 1 (OERR) of the RCSTA register detects overrun

;Bit 2 (FERR) of the RCSTA register detects framing error

;At this point no error was detected

;Received data is in the USART RCREG register

;error because FERR framing error bit is set

;can do special error handling here - this code simply clears

14.5.6 SerIntLCD Program

;File name: SerIntLCD.asm

;Last revision: May 14, 2006

;Author: Julio Sanchez

;Processor: 16F877

;Interrupt-driven version of the SerComLCD program

;Description:

;Decode 4 x 4 keypad, display scan code in LCD, and send

;ASCII character through the serial port. Also receive

;data through serial port and display on LCD. LCD lines

;are scrolled by program.

;Default serial line setting:

;Program to uses 4-bit PIC-to-LCD interface.

;Code assumes that LCD is driven by Hitachi HD44780

;controller and PIC 16F977. Display supports two lines

;each one with 20 characters. The length, wiring and base

;address of each display line is stored in #define

;statements. These statements can be edited to accommodate

;a different setup.

;Keypad switch wiring (values are scan codes):

;—- KEYPAD —

;|_________________ port B7 |

;Operations:

;1. Key press action generates a scan code in the range

;0x0 to 0xf.

;2. Scan code is converted to an ASCII digit and displayed

;on the LCD. LCD lines are scrolled as end-of-line is

;reached.

;3. Characters typed on the keypad are also transmitted

;through the serial port.

;4. Received characters generate an interrupt. The interrupt

;handler displays received characters on the LCD.

;

;WARNING:

;Code assumes 4Mhz clock. Delay routines must be

;edited for faster clock. Clock speed also determines

;values for baud rate setting (see spbrgVal constant).

;===========================

;16F877 switches

;===========================

; Switches used in __config directive:

;_PWRTE_OFF

;_PWRTE_OFF

;* _CPD_OFF

;OSCILLATOR CONFIGURATIONS:

;|

;|_____ * indicates setup values presently selected

processor 16f877 ; Define processor

#include <p16f877.inc>

__CONFIG _CP_OFF & _WDT_OFF & _BODEN_OFF & _PWRTE_ON & _HS_OSC & _WDT_OFF & _LVP_OFF & _CPD_OFF

;__CONFIG directive is used to embed configuration data

;within the source file. The labels following the directive

;are located in the corresponding .inc file. ;============================================================

; M A C R O S

;============================================================ ; Macros to select the register banks

;=====================================================

;=====================================================