PIC Getting Started 3, SPI Communication and Serial Port Debugging Experiment

program:

//Suitable for 3EPIC experiment board, configure the MSSP module of PIC microcontroller to work in SPI master mode,
//The received parallel data is sent out as serial data through the SD0 port through a parallel/serial conversion shift register (74HC165),
//PIC stores the serial data in the register and sends it to the D port to drive the LED to light up.
#include
#include
volatile unsigned char data;
/****************************************************************************/
/*Function name: SPIINT() */
/*Function: SPI initialization */
/*****************************************************************************/

void SPIINIT()
{
 PIR1=0;  
 SSPCON=0x30; /*SSPEN=1;CKP=1;FOSC/4 */  
      
 SSPSTAT=0xC0; 
 TRISC=0x10; //SDO pin is input, SCK pin is output 
}
/*************************************************************************/
/*Function name: initial() */
/*Function: Initialize the input and output ports of the system */
/*************************************************************************/

void initial()
{
 TRISE=0x00; //Control PL port
 TRISD=0x00; /*Port D connected to LED is output*/    
 INTCON=0x00; //Disable all interrupts
}
/****************************************************************************/
/*Function name: SPIN() */
/*Function: SPI receiving subroutine */
/*****************************************************************************/

void SPIN()
{
 RE1=0; //PL low, parallel data is placed in
 RE1=1; //PL high, parallel data is read out
 SSPBUF=0; //Start SPI, this operation is only used to clear the BF bit of SSPSTAT, so the actual data in W is not important 
 do
 {
   ;
 }while(SSPIF==0); //Wait for the transmission to be completed 
SSPIF=0; //Clear SSPIF flag
data=SSPBUF;    
}
/*****************************************************************************/
/*Function name: SPIOUT() */
/*Function: Display the data received by SPI on 8 light-emitting diodes through port D */
/*****************************************************************************/

void SPIOUT(int data)
{
 PORTD=~data;
}
/************************************************************************/
/*Function name: main() */
/*Function: Main function */
/*************************************************************************/

main()
{
 initial(); //System initialization
 RE0=1; //LED enable terminal 
 SPIINIT(); //SPI initialization
 while (1)
  {
  SPIN(); //SPI receives external data
  SPIOUT(data); //Send data display
  }  
}

This needs to be connected to 74HC595 separately, but when it is running, it is the fast motion (rapid fire) of 74HC595, so it does not display from 1 to the end, but directly displays the end number, and the slow motion has not been adjusted.

program:

//Suitable for 3ePIC development board, to realize the display of digital tube in SPI mode
//The downstream device is 74HC595 (8-bit serial to parallel register) experimental SPI communication
#include
#include
static volatile int table[]={0X3F,0X06,0X5B,0X4F,0X66,0X6D,0X7D,0X07,0X7F,0X6F,0X77,0X7C,0X39,0X5E,0X79,0X71};
volatile unsigned char data; 
#define PORTAIT(adr,bit) ((unsigned)(&adr)*8+(bit)) //*Absolute addressing bit operation instruction*/
static bit PORTA_5 @ PORTAIT(PORTA,5); 
/*************************************************************************/
/*Function name: SPIINT() */
/*Function: Initialize SPIi */
/************************************************************************/
void SPIINIT()
{
 PIR1=0;  
 SSPCON=0x30; /*Allow SPI to work in master mode, SSPEN=1; CKP=1, */
       /* FOSC/4 */
 SSPSTAT=0xC0;
 TRISC=0x00; /* SDO pin is output, SCK pin is output*/
}
/*****************************************************************************/
/*Function name: initial() */
/*Function: Initialize the input and output ports of the system */
/*************************************************************************/
void initial()
{
 TRISA=0x00; //Set port A to output
 TRISB=0x00;
 INTCON=0x00; //Disable all interrupts
       // LACK sends low level to prepare for latching
}
/****************************************************************************/
/*Function name: SPILED() */
/*Function: SPI sends data */
/****************************************************************************/
void SPILED(int data)
{
 SSPBUF=data; //Start sending
 do
 {
  ;
 }while(SSPIF==0); //Wait for sending to be completed
SSPIF=0; //Clear SSPIF flag
}

void DELAY()
{
 unsigned int j;
 for(j=0;j<50000;j++)
 continue;
}

/*******************************************************************************/
/*Function name: main() */
/*Function: main program */
/***************************************************************************/
main()
{
 unsigned int i;

 initial(); //System initialization
 RB2=0;
 SPIINIT(); //SPI initialization 
  for(i=0;i<8;i++) //Continuously send 8 data
   { 
  data=table[i]; //Get the segment code to be displayed through array conversion 
  SPILED(data); //Send the display segment code to display */
   }
 PORTA_5=0; 
 DELAY();
 PORTA_5=1; //Finally, give the latch signal to indicate that the display task is completed
}

Serial port debugging experiment:

Experimental Procedure:

//Purpose of the experiment: Get familiar with USART communication
//Use the "Serial Port Debug Assistant" to assist in the work
//Serial Port Debug Assistant sends data to 877, and 877 forwards it back to the Serial Port Assistant after receiving it
//Hardware requirements: All DIP switches S7 are set to ON, and other DIP switches are set to OFF

#include //Includes the predefined
 __CONFIG(0x1832) internal resources of the MCU;        
//Chip configuration word, watchdog off, power-on delay on, power-off detection off, low voltage programming off, encryption, 4M crystal HS oscillation

//---------------------------------------------
//Main program
void main()
 {
  TRISC=0XFF; //Set the direction of port C to all outputs
  SPBRG=0XC; //Set the baud rate to 19200BPS
  TXSTA=0X24; //Enable serial port transmission, select high-speed baud rate
  RCSTA=0X90; //Enable serial port operation, continuous reception
  RCIE=0X1; //Enable receive interrupt
  GIE=0X1; //Open global interrupt
  PEIE=0X1; //Enable external interrupt
  while(1) //Wait for interrupt
   {;}
  }

//--------------------------------------------
//Interrupt function
void interrupt usart(void)
  {
   if(RCIE&&RCIF) //Judge whether it is a serial port receive interrupt
     {
      TXREG=RCREG; //Send the received data back
     }
   }