display image sent over Bluetooth

[lydie]

Hi,

I want to display an image sent over Bluetooth on my screen which uses the driver st7735. So I have an application which can send images, and I receive data in the function nus_data_handler. With this application, I send array of 20 data (two first and last data are control data to know that an image is sent). The data sent are 4bytes for 1 pixel so RGBα, and 8 bites for red, 8 for green, 8 for blue and 8 for alpha. I display an image with the function nrf_gfx_bmp565_draw, so pixel format is RGB565. When I received data (R, G, and B), I convert these 3 data to one and transform them to RGB565 with this:

RGB16(red, green, blue) (((red >> 3) << 11) | ((green >> 2) << 5) | (blue >> 3))

I don't care about α for the conversion. After, I have the value of one pixel. I need to save this pixel value, so I created an array image_received of the image size (80x160 = 12800) with all element are 0xFFFF (white) in another file include in main.c. When I have the value of one pixel, I replace the element of image_received by this value. So at the end, I should have in image_received the image received by Bluetooth. When I try to display image_received, it doesn't work: it is the image of the beginning which is displayed, image_received is not updated. Here is my code who receive and display data.

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if (p_evt->type == BLE_NUS_EVT_RX_DATA) {

uint32_t err_code;

NRF_LOG_DEBUG("Received data from BLE NUS. Writing data on UART.");

NRF_LOG_HEXDUMP_DEBUG(p_evt->params.rx_data.p_data, p_evt->params.rx_data.length);

printf("Received rx of length:%d\r\n", p_evt->params.rx_data.length);

int pixel, red = -1, green = -1, blue = -1;

for (int i = 0; i < p_evt->params.rx_data.length; i++) {

printf("debug received %d at %d\r, i %d\n", p_evt->params.rx_data.p_data[i], p_evt->params.rx_data.length,i);

array_data[i]=p_evt->params.rx_data.p_data[i];

if ((i==2)|(i==6)|(i==10)){

red = array_data[i];

//printf("red %d \n", red);

}

if ((i==3)|(i==7)|(i==11)){

green =array_data[i];

//printf("green %d \n", green);

}

if ((i==4)|(i==8)|(i==12)){ //green ||(i==8)||(i=12)||(i==16))

blue =array_data[i];

// printf("blue %d \n", blue);

pixel = RGB16(red, green, blue); //convert rdb24 to rgb16

XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

if (p_evt->type == BLE_NUS_EVT_RX_DATA) {
    uint32_t err_code;
    NRF_LOG_DEBUG("Received data from BLE NUS. Writing data on UART.");
    NRF_LOG_HEXDUMP_DEBUG(p_evt->params.rx_data.p_data, p_evt->params.rx_data.length);
    printf("Received rx of length:%d\r\n", p_evt->params.rx_data.length);
    int pixel, red = -1, green = -1, blue = -1;
    for (int i = 0; i < p_evt->params.rx_data.length; i++) {
      printf("debug received %d at %d\r, i %d\n", p_evt->params.rx_data.p_data[i], p_evt->params.rx_data.length,i);
      array_data[i]=p_evt->params.rx_data.p_data[i];
      if ((i==2)|(i==6)|(i==10)){ 
          red = array_data[i];
          //printf("red %d \n", red);
      }
       if ((i==3)|(i==7)|(i==11)){ 
              green =array_data[i];
              //printf("green %d \n", green);
      }
      if ((i==4)|(i==8)|(i==12)){ //green ||(i==8)||(i=12)||(i==16))
              blue =array_data[i];
             // printf("blue %d \n", blue);
              pixel = RGB16(red, green, blue); //convert rdb24 to rgb16
             // printf("pixel %d \n", pixel);
              
              image_received[cpt_pixel] = pixel;
             // printf("valeur image %d \n", image_received[cpt_pixel]);
              cpt_pixel ++;
              printf("cpt pixel %d \n", cpt_pixel);
                         
      }
   if ((cpt_pixel == 100)|(cpt_pixel==150)|(cpt_pixel==200)){
      screen_clear(BLACK);
      nrf_gfx_background_set(p_lcd, (uint16_t const*)image_received);
      printf("display !!");
   }
   }

So I don't know how can I display an image sent over Bluetooth. On the internet, I only find answers to display an image on the application sent by nrf52; but my issue is the other way around. I think it's better to send data received in flash memory, so I can send an array with sd_flash_write, but I still have to stock data in image_received and after reading into the flash and display, but I don't know how to do it.

I use nrf 52832, with PCA10040, s 132, sdk15.3 and Segger embedded.