WhyCan Forum(哇酷开发者社区)

for (x=0; x<num_bytes; x++)
    {
        sendbuf[x]= i&0xff;
        i++;
    }

uint8_t PCD_ReadRegister(spi_device_handle_t spi, uint8_t reg)
{
    uint8_t value;
    esp_err_t ret;
    spi_transaction_t t;
    memset(&t, 0, sizeof(t));       //Zero out the transaction
   
    reg = 0x80 | reg;
   
    t.length=8;                     //Command is 8 bits
    t.tx_buffer=&reg;               //The data is the cmd itself
    t.user=(void*)0;                //D/C needs to be set to 0
    ret=spi_device_transmit(spi, &t);  //Transmit!

   
    uint8_t zero = 0;
    uint8_t kkk = 0;
    t.tx_buffer = &zero;
    t.rx_buffer = &kkk;
    t.length=8*1;
    t.flags = SPI_TRANS_USE_RXDATA;
    ret = spi_device_transmit(spi, &t);
    assert( ret == ESP_OK );
   
    return *(uint8_t*)t.rx_data;;
}

晕哥 说：

uint8_t PCD_ReadRegister(spi_device_handle_t spi, uint8_t reg)
{
    uint8_t value;
    esp_err_t ret;
    spi_transaction_t t;
    memset(&t, 0, sizeof(t));       //Zero out the transaction
   
    reg = 0x80 | reg;
   
    t.length=8;                     //Command is 8 bits
    t.tx_buffer=&reg;               //The data is the cmd itself
    t.user=(void*)0;                //D/C needs to be set to 0
    ret=spi_device_transmit(spi, &t);  //Transmit!

   
    uint8_t zero = 0;
    uint8_t kkk = 0;
    t.tx_buffer = &zero;
    t.rx_buffer = &kkk;
    t.length=8*1;
    t.flags = SPI_TRANS_USE_RXDATA;
    ret = spi_device_transmit(spi, &t);
    assert( ret == ESP_OK );
   
    return *(uint8_t*)t.rx_data;;
}

昨晚测试一会， 没读出寄存器值, 真想去撞南墙...

RC522读寄存器，貌似要左移，不能直接写寄存器地址, 你看下手册

晕哥 说：

陆闻天 说：

RC522读寄存器，貌似要左移，不能直接写寄存器地址, 你看下手册

https://whycan.cn/files/201710/13/20171013113805.png
果然是啊， 谢谢陆大神, 喝水不忘挖坑人。
晚上回家试一试.

别客气, 那是因为我刚刚做完RC522项目