ESP32-S3 + ST7789 (240x240) - Severe "Rainbow Static" noise when drawing Camera frames

[dokf08]

Hi Bodmer,
First of all, thank you for this amazing library.

I am trying to build a digital camera using an ESP32-S3 (N16R8), an OV2640 camera, and a standard ST7789 240x240 IPS display.

The Problem:
The screen works perfectly when drawing static text or graphics (User_Setup test works fine). However, as soon as I start the Camera and try to push frames to the screen (using tft.pushImage), the image is overwhelmed by "rainbow static" or noise. It looks like electrical interference or a timing mismatch.

What I have tried:
Lowered SPI Frequency to 20MHz and 10MHz.
Lowered Camera XCLK to 10MHz to reduce interference.
Used a custom "Magic Init" sequence (adjusting Porch control and Gamma) found in another driver file, which helped slightly but didn't fix it.
Forced TFT_RGB_ORDER TFT_BGR and TFT_INVERSION_ON.

My Setup:
Board: ESP32-S3 Dev Module (N16R8) + Built In Camera OV2640 + SD Card Slot
Library Version: Latest

Wiring (HSPI):
SDA (MOSI): GPIO 47
SCL (SCLK): GPIO 21
DC: GPIO 41
RST: GPIO 42
(MISO/CS are not available)

My User_Setup.h:

#define ST7789_DRIVER
#define TFT_WIDTH 240
#define TFT_HEIGHT 240
#define TFT_RGB_ORDER TFT_BGR
#define TFT_INVERSION_ON

#define TFT_MOSI 47
#define TFT_SCLK 21
#define TFT_DC 41
#define TFT_RST 42
#define TFT_CS -1

#define LOAD_GLCD
#define SPI_FREQUENCY 20000000 // I have tried lower

The Code Snippet (Loop):
// Using native rom/tjpgd.h decoder
static UINT tjd_output(JDEC *jd, void *bitmap, JRECT rect) {
tft.pushImage(rect->left, rect->top, rect->right - rect->left + 1, rect->bottom - rect->top + 1, (uint16_t)bitmap);
return 1;
}

void loop() {
camera_fb_t *fb = esp_camera_fb_get();
if (fb) {
drawFrame(fb); // Calls tjd_output
esp_camera_fb_return(fb);
}
}

The Visuals :

https://github.com/user-attachments/assets/6bacd2c0-7e2d-4005-900d-929ffe8ce28e

Is there a specific initialization command or SPI setting I am missing for the ESP32-S3 to handle the high-speed camera data alongside the screen update?

[Bodmer]

It looks like a resource conflict (shared GPIO), internal to ESP32 S3 hardware conflicts or interrupts are firing during screen update. I suspect it is not electrical noise unless that camera is particularly sensitive. The blockiness is probably becuase you are decoding a jpeg? (handed in bocks of 8x8 or 16x16 pixels.

What is the program flow for updated to the screen. Can you grab an image to a sprite then, when the camera is not being accessed, send the sprite to the screen.

[dokf08]

Hi Bodmer, thank you for the reply!

1. Regarding the Blockiness:Yes, you are correct. I am decoding a JPEG stream (PIXFORMAT_JPEG from the OV2640) using the native rom/tjpgd.h decoder.

2. Regarding Resource Conflicts:I am using an ESP32-S3 N16R8. I have checked my wiring to avoid direct GPIO conflicts, but I suspect you are right about internal hardware conflicts (DMA/Interrupts).

• Camera Pins: Standard (XCLK 15, PCLK 13, Data on 11,9,8,10,12,18,17,16).
• Screen Pins: I am using TFT_MOSI 47, TFT_SCLK 21, TFT_DC 41, TFT_RST 42.

3. Current Program Flow:Currently, my loop looks like this: * esp_camera_fb_get() (Grab the JPEG buffer). * jd_decomp() (Decode the JPEG blocks).

• Inside the decoder callback: I am writing pixels to a TFT_eSprite (Canvas).
• After decoding is finished, I call sprite.pushSprite(0,0) to send it to the screen.
• esp_camera_fb_return().

Your Suggestion:
You mentioned "when the camera is not being accessed, send the sprite to the screen."
Since esp_camera_fb_get grabs a frame but the camera hardware (XCLK/PCLK) keeps running in the background to fill the next buffer, does this create the interrupt conflict?
Is there a recommended way to "pause" the camera driver momentarily to grant the SPI bus (Screen) exclusive access during the pushSprite phase?
Thanks again for your help!

[dokf08]

this is my user_setup.h

#define USER_SETUP_INFO "S3_Camera"

#define ST7789_DRIVER
#define TFT_WIDTH  240
#define TFT_HEIGHT 240

#define USE_HSPI_PORT 
#define TFT_MISO -1
#define TFT_MOSI 47
#define TFT_SCLK 21
#define TFT_CS   -1
#define TFT_DC   41
#define TFT_RST  42
#define TFT_BL   -1 

#define LOAD_GLCD
#define SPI_FREQUENCY  20000000 

And this is my full code

#include "esp_camera.h"
#include <SPI.h>
#include <TFT_eSPI.h> 
#include "rom/tjpgd.h"

#define PWDN_GPIO_NUM -1
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM  15
#define SIOD_GPIO_NUM  4
#define SIOC_GPIO_NUM  5
#define Y2_GPIO_NUM 11
#define Y3_GPIO_NUM 9
#define Y4_GPIO_NUM 8
#define Y5_GPIO_NUM 10
#define Y6_GPIO_NUM 12
#define Y7_GPIO_NUM 18
#define Y8_GPIO_NUM 17
#define Y9_GPIO_NUM 16
#define VSYNC_GPIO_NUM 6
#define HREF_GPIO_NUM  7
#define PCLK_GPIO_NUM  13

TFT_eSPI tft = TFT_eSPI(); 
uint8_t *work_buffer = NULL; 

static UINT tjd_input(JDEC *jd, BYTE *buff, UINT nd) {
  struct { uint8_t *buf; int len; int pos; } *dev = (typeof(dev))jd->device;
  if (!buff) { dev->pos += nd; return nd; }
  if (dev->pos + nd > dev->len) nd = dev->len - dev->pos;
  memcpy(buff, dev->buf + dev->pos, nd);
  dev->pos += nd;
  return nd;
}

static UINT tjd_output(JDEC *jd, void *bitmap, JRECT *rect) {
  tft.pushImage(rect->left, rect->top, rect->right - rect->left + 1, rect->bottom - rect->top + 1, (uint16_t*)bitmap);
  return 1;
}

void drawFrame(camera_fb_t *fb) {
  JDEC jd;
  struct { uint8_t *buf; int len; int pos; } dev = { fb->buf, (int)fb->len, 0 };
  if (jd_prepare(&jd, tjd_input, work_buffer, 3100, &dev) == JDR_OK) {
    jd_decomp(&jd, tjd_output, 0); 
  }
}

void magicInit() {
  tft.writecommand(0x11); delay(120); 
  tft.writecommand(0xB2); tft.writedata(0x0C); tft.writedata(0x0C); tft.writedata(0x00); tft.writedata(0x33); tft.writedata(0x33);
  tft.writecommand(0xB7); tft.writedata(0x35);
  tft.writecommand(0xBB); tft.writedata(0x28);
  tft.writecommand(0xC0); tft.writedata(0x0C);
  tft.writecommand(0xC2); tft.writedata(0x01);
  tft.writecommand(0xC3); tft.writedata(0x10);
  tft.writecommand(0xC4); tft.writedata(0x20);
  tft.writecommand(0xC6); tft.writedata(0x0F);
  tft.writecommand(0xD0); tft.writedata(0xA4); tft.writedata(0xA1);
  tft.writecommand(0xE0); tft.writedata(0xD0); tft.writedata(0x00); tft.writedata(0x02); tft.writedata(0x07); tft.writedata(0x0A); tft.writedata(0x28); tft.writedata(0x32); tft.writedata(0x44); tft.writedata(0x42); tft.writedata(0x06); tft.writedata(0x0E); tft.writedata(0x12); tft.writedata(0x14); tft.writedata(0x17);
  tft.writecommand(0xE1); tft.writedata(0xD0); tft.writedata(0x00); tft.writedata(0x02); tft.writedata(0x07); tft.writedata(0x0A); tft.writedata(0x28); tft.writedata(0x31); tft.writedata(0x54); tft.writedata(0x47); tft.writedata(0x0E); tft.writedata(0x1C); tft.writedata(0x17); tft.writedata(0x1B); tft.writedata(0x1E);
  tft.writecommand(0x29); 
}

void setup() {
  Serial.begin(115200);
  
  tft.init();
  tft.setRotation(1); 
  tft.writecommand(0x36); tft.writedata(0x08); // BGR Fix
  magicInit(); 
  tft.setSwapBytes(true); 
  tft.fillScreen(TFT_BLACK); 

  camera_config_t config;
  config.ledc_channel = LEDC_CHANNEL_0;
  config.ledc_timer = LEDC_TIMER_0;
  config.pin_d0 = Y2_GPIO_NUM; config.pin_d1 = Y3_GPIO_NUM;
  config.pin_d2 = Y4_GPIO_NUM; config.pin_d3 = Y5_GPIO_NUM;
  config.pin_d4 = Y6_GPIO_NUM; config.pin_d5 = Y7_GPIO_NUM;
  config.pin_d6 = Y8_GPIO_NUM; config.pin_d7 = Y9_GPIO_NUM;
  config.pin_xclk = XCLK_GPIO_NUM; config.pin_pclk = PCLK_GPIO_NUM;
  config.pin_vsync = VSYNC_GPIO_NUM; config.pin_href = HREF_GPIO_NUM;
  config.pin_sscb_sda = SIOD_GPIO_NUM; config.pin_sscb_scl = SIOC_GPIO_NUM;
  config.pin_pwdn = PWDN_GPIO_NUM; config.pin_reset = RESET_GPIO_NUM;
  
  config.xclk_freq_hz = 10000000; // 10MHz (Safe Speed)
  config.pixel_format = PIXFORMAT_JPEG;
  config.frame_size = FRAMESIZE_240X240; 
  config.jpeg_quality = 10;
  config.fb_count = 2; 
  config.grab_mode = CAMERA_GRAB_LATEST; 
  
  esp_camera_init(&config);
  delay(500);
  sensor_t *s = esp_camera_sensor_get();
  s->set_saturation(s, -2); 
  s->set_special_effect(s, 2); 
  s->set_contrast(s, 2); 
  s->set_brightness(s, 1);     
  s->set_agc_gain(s, 1);   
  s->set_aec2(s, 1);        

  //I use this because its the better colour even though there is still a rainbow static

  work_buffer = (uint8_t*)heap_caps_malloc(3100, MALLOC_CAP_SPIRAM);
}

void loop() {
  camera_fb_t *fb = esp_camera_fb_get();
  if (fb) {
    drawFrame(fb);
    esp_camera_fb_return(fb);
  }
}

[Bodmer]

It looks OK. Maybe try without needing to decode the jpeg. Set pixel format to PIXFORMAT_RGB565 and use pushImage to send data to screen. What result does that give?