AVR SPI接收数据时实现接收数据数组元素自增标记的方法求助

Hey there! Let's work through your SPI problem together. I get that you need to capture the data received during SPI exchanges, store it in an array, and increment the corresponding element to mark it as received. Here's a step-by-step solution tailored to your existing code:

Key Background #

First, remember that AVR's SPI is full-duplex—every time you send a byte with SPI0_exchangeData(), you also receive a byte in return. Your original code was ignoring that returned value; we'll fix that to capture and process the received data.

Modified Code Implementation #

Let's adjust your code to add the receive handling and element increment logic:

#include <xc.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <stdio.h>

void SPI0_init(void);
void LTCSelect(void);
void LTCDeselect(void);
uint8_t SPI0_exchangeData(uint8_t data);
void spi_transfer_and_process(uint8_t tx_data[], uint8_t length, uint8_t rx_buffer[]);

// Define your transmit buffer as before
uint8_t buffer[] = { 10, 20, 30};

// Receive buffer to store incoming data (match length of transmit buffer)
uint8_t rx_buffer[sizeof(buffer)] = {0};

// Optional: If you want to count occurrences of each received byte (e.g., track how many times 0x0A was received)
// uint8_t rx_data_counts[256] = {0};

void SPI0_init(void) {
 PORTA.DIR |= PIN4_bm; /* Set MOSI pin direction to output (output to LTC2983) */
 PORTA.DIR &= ~PIN5_bm; /* Set MISO pin direction to input (input form LTC2983) */
 PORTA.DIR |= PIN6_bm; /* Set SCK pin direction to output (output to LTC2983) */
 PORTA.DIR |= PIN7_bm; /* Set CS pin direction to output (output to LTC2983) */
 SPI0.CTRLA = SPI_CLK2X_bm /* Enable double-speed */
 | SPI_DORD_bm /* LSB is transmitted first */
 | SPI_ENABLE_bm /* Enable module */
 | SPI_MASTER_bm /* SPI module in Master mode */
 | SPI_PRESC_DIV16_gc; /* System Clock divided by 16 */
}

uint8_t SPI0_exchangeData(uint8_t data) {
 SPI0.DATA = data;
 while (!(SPI0.INTFLAGS & SPI_IF_bm)) /* waits until data is exchanged*/
 {
 }
 return SPI0.DATA;
}

void LTCSelect(void) {
 PORTA.OUT &= ~PIN7_bm; // Set SS pin value to LOW
}

void LTCDeselect(void) {
 PORTA.OUT |= PIN7_bm; // Set SS pin value to HIGH
}

// New function: Transmit data AND process received data
void spi_transfer_and_process(uint8_t tx_data[], uint8_t length, uint8_t rx_buffer[]) {
 for(uint8_t i = 0; i < length; i++) {
    // Send a byte and capture the received byte
    uint8_t received_byte = SPI0_exchangeData(tx_data[i]);
    
    // Store the received byte in the buffer
    rx_buffer[i] = received_byte;
    
    // Increment the element to mark it as received (modifies the stored value)
    rx_buffer[i]++;

    // Optional: If you want to count how many times each byte was received, use this instead:
    // rx_data_counts[received_byte]++;
 }
}

int main(void) {
 SPI0_init();
 while(1){
  LTCSelect();
  // Use our new function instead of sendArray
  spi_transfer_and_process(buffer, sizeof(buffer), rx_buffer);
  LTCDeselect();
  
  // Optional: Add code here to verify results (e.g., print rx_buffer via UART)
 }
}

How It Works #

1. Capturing Received Data: The SPI0_exchangeData() function returns the byte received during the exchange—we store this value in received_byte.
2. Storing to Array: We save received_byte into the rx_buffer at the same index as the byte we sent (so the first sent byte pairs with the first received byte).
3. Marking as Received: We increment the element in rx_buffer right after storing it—this modifies the stored value to act as a marker that it was received. If you instead want to count occurrences of each received byte (without modifying the original data), use the optional rx_data_counts array instead.

Notes #

• Make sure rx_buffer has at least the same length as your transmit buffer to avoid array out-of-bounds errors.
• If you need to preserve the original received data while marking it, you could use a separate array for markers (e.g., uint8_t rx_markers[sizeof(buffer)] = {0}; and increment rx_markers[i] instead of modifying rx_buffer[i]).

内容的提问来源于stack exchange，提问作者Study only