The 16F877 is a microcontroller developed by Microchip Technology, which is capable of supporting the Serial Peripheral Interface (SPI) communication protocol. The SPI protocol is a synchronous serial communication protocol that allows devices to exchange data with each other. In order to use the SPI protocol with the 16F877 microcontroller, you need to follow these steps:
Configure the SPI pins: The 16F877 has dedicated pins for SPI communication, which are RB0 (SS), RB1 (SDO), RB2 (SDI), and RB3 (SCK). You need to configure these pins as digital I/O pins and set their direction as input or output, depending on the functionality you want to implement.
Configure the SPI module: The 16F877 has an SPI module that can be configured using the SPBRG (SPI Baud Rate Generator) register. This register sets the clock speed for the SPI communication, and its value depends on the system clock frequency and the desired baud rate. You also need to configure the SPI control register (SSPSTAT) and the SPI control register (SSPCON), which define the SPI mode, clock polarity, and data order.
Implement SPI communication: Once the SPI pins and module are configured, you can implement SPI communication between the 16F877 microcontroller and other SPI devices. To send data from the 16F877 to another device, you need to write the data to the SPI buffer register (SSPBUF) and then wait for the transfer to complete. To receive data from another device, you need to read the data from the SPI buffer register after the transfer has completed.
Here is some sample code in C language for implementing SPI communication using the 16F877 microcontroller:
#include <pic16f877.h>
#include <xc.h>
void spi_init()
{
// Configure SPI module
SSPCON = 0b00100000; // SPI Master, clock = Fosc/4
SSPSTAT = 0b00000000; // Data sampled at middle of data output time
// Configure pins
TRISC5 = 0; // SDO as output
TRISC4 = 1; // SDI as input
TRISC3 = 0; // SCK as output
}
void spi_write(char data)
{
SSPBUF = data; // Write data to buffer
while (!SSPIF); // Wait for transmission to complete
SSPIF = 0; // Clear flag
}
char spi_read()
{
SSPBUF = 0x00; // Write dummy data to initiate read
while (!SSPIF); // Wait for reception to complete
SSPIF = 0; // Clear flag
return SSPBUF; // Return received data
}
void main()
{
spi_init();
spi_write(0x55); // Write data to SPI
char data = spi_read(); // Read data from SPI
}
Note that this is just a simple example, and the specific configuration of the SPI module will depend on the requirements of your particular project.
