Node32s connect with tft and max6635

foccacia · September 13, 2021, 4:39pm

Update: I had removed the LED.

hi everyone,
i got some trouble when connecting 2 spi parts (tft screen,max6635 thermcouple)to arduino board.

After connecting, both parts was not operated: TFT can not show the print, TC only show 0.0

I had reviewed some of information about the spi communication and its seems the chip selecting ( cs ) issue, please help and suggest a solution, many thanks!

#include <SPI.h>
#include "Adafruit_GFX.h"
#include <Adafruit_ST7735.h> // Hardware-specific library for ST7735
#include "max6675.h"



#define BLACK       0x0000
#define BLUE        0x001F
#define RED         0xF800
#define GREEN       0x07E0
#define CYAN        0x07FF
#define YELLOW      0xFFE0
#define WHITE       0xFFFF


//TFT setting for NODE32s

#define TFT_DC  4        // register select (stands for Data Control perhaps!)
#define TFT_SCLK 18         // SPI clock
#define TFT_MOSI 23         // SPI Data
#define TFT_CS   16        // Display enable (Chip select), if not enabled will not talk on SPI bus
#define TFT_RST   0         // Display reset pin, you can also connect this to the Arduino reset
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);

// MAX6625 setting for node32s
int thermoDO = 19; //MISO


int thermoCS1 = 5;
int thermoCS2 = 17;

MAX6675 thermocouple1(TFT_SCLK, thermoCS1, thermoDO);
MAX6675 thermocouple2(TFT_SCLK, thermoCS2, thermoDO);


void setup() {
  Serial.begin(9600);
  SPI.begin();

  /* pinMode(TFT_CS, OUTPUT);
    pinMode(thermoCS1, OUTPUT);
    pinMode(thermoCS2, OUTPUT);

    digitalWrite (thermoCS1, LOW);
    digitalWrite (thermoCS2, LOW);
    digitalWrite (TFT_CS, LOW);  */

  tft.initR(INITR_BLACKTAB);
  tft.setRotation(3);
}

void loop() {

  ;
  tft.fillScreen(BLACK);
  tft.setTextColor(BLACK, WHITE);
  tft.setTextSize(1);
  tft.setCursor ( 0, 2);

  tft.print ( thermocouple1.readCelsius());
  tft.setCursor ( 0, 3);
  tft.print ( thermocouple2.readCelsius());

  Serial.print("C = ");
  Serial.println(thermocouple1.readCelsius());
  Serial.println(thermocouple2.readCelsius());

  delay(2000);

}

david_prentice · September 13, 2021, 5:42pm

Please post a link to the actual display that you have bought.

Displays vary. I don't want to guess.

A Node32s and a 16x2 with I2C backpack look normal. But there is no harm in providing links.

David.

Idahowalker · September 13, 2021, 6:01pm

I am sorry from the description of your issue, I am unable to reproduce your code or draw a schematic of your project. Perhaps you'd be so kind as to post your code IN CODE TAGS, and post a schematic? Please.

foccacia · September 15, 2021, 2:51pm

posted the code, many thanks!

Idahowalker · September 15, 2021, 3:06pm

The posted code, lacks code tags.

foccacia · September 15, 2021, 3:14pm

Updated , thanks.

By the way, I am looking for solution how to display temperature value on the TFT screen, and I am stuck at SPI setting i think.. hope you can help.

Idahowalker · September 15, 2021, 3:23pm

Why do this? The individual drivers will handle CS functions.

Did you get a single max to work before trying to get the 2nd one to work?

You are connecting 3 SPI devices not 2, as a note.

Double entry?
Leaving the other devices connected, if you comment out the TFT code and one t-couple are you able to get prints of the other t-couples data out put?

You do not need that.

Idahowalker · September 15, 2021, 3:24pm

What does that mean?

Idahowalker · September 15, 2021, 3:29pm

You know the ESP32 has 2 SPI ports? The SPI ports are VSPI and HSPI. You are using VSPI for all 3 devices. You might consider putting the t-couples on the HSPI bus.

foccacia · September 15, 2021, 3:35pm

I had tried using the above coding, but only get print on TFT or t- couple in serial,

I wondering how to get show on the TFT.

I had tried google " Multi SPI device on arduino", most said device required individual CS pin .

Idahowalker · September 15, 2021, 3:38pm

Sorry, I do not not understand your issue. Please restate your issue.

foccacia · September 15, 2021, 3:41pm

The issue is SPI TFT and SPI thermocouple connect together on ESP32 board, both devices can not operate by using code above.

Idahowalker · September 15, 2021, 3:57pm

What does that mean?

Do you get error messages? Be a bit more descriptive of your problem.

Besides the mentions above, I do not see anything glaring obviously wrong with your code. There are a few things I'd do differently, like GPIO pin choices. The pins you used should work fine.

So right now that your code looks good I require more input .

I strongly recommend you use the other SPI buss for the t-couple thingies. I have, in the past, ran into the display units that use extra pins sometimes do not play nice with the SPI buss.

foccacia · September 15, 2021, 4:13pm

Thanks for the reply,

No error message shown, but the TFT screen and TC did not shown the print on screen , and TC did not show data in Serial
Try using SPI buss later

Idahowalker · September 15, 2021, 4:28pm

Cool, things are a lot more clear now.

Just making sure I am understanding correctly you tired to print to the tft and send to the serial monitor at the same time?

Start with not using GPIO_NUM_17 and GPIO_NUM_16 as cs pins. Use GPIO_NUM_26 and GPIO_NUM_27.

Post your code changes/updates in a new post, I cannot read your screen.

foccacia · September 15, 2021, 4:30pm

YES, keep sending TC temp value to TFT and serial at the same time

Updated the CS pins , but still the same, nothing change


#include <SPI.h>
#include "Adafruit_GFX.h"
#include <Adafruit_ST7735.h> // Hardware-specific library for ST7735
#include "max6675.h"



#define BLACK       0x0000
#define BLUE        0x001F
#define RED         0xF800
#define GREEN       0x07E0
#define CYAN        0x07FF
#define YELLOW      0xFFE0
#define WHITE       0xFFFF


//TFT setting for NODE32s

#define TFT_DC  4        // register select (stands for Data Control perhaps!)
#define TFT_SCLK 18         // SPI clock
#define TFT_MOSI 23         // SPI Data
#define TFT_CS   27        // Display enable (Chip select), if not enabled will not talk on SPI bus
#define TFT_RST   0         // Display reset pin, you can also connect this to the Arduino reset
Adafruit_ST7735 tft = Adafruit_ST7735(TFT_CS, TFT_DC, TFT_RST);

// MAX6625 setting for node32s
int thermoDO = 19; //MISO
int thermoCLK = 18;
int thermoCS1 = 5;

MAX6675 thermocouple1(thermoCLK, thermoCS1, thermoDO);



void setup() {
  Serial.begin(9600);


  pinMode(TFT_CS, OUTPUT);
  pinMode(thermoCS1, OUTPUT);

  tft.initR(INITR_BLACKTAB);
}

void loop() {
  digitalWrite (TFT_CS, HIGH);
  
  tft.fillScreen(BLACK);
  tft.setTextColor(BLACK, WHITE);
  tft.setTextSize(1);
  tft.setCursor ( 0, 2);
  delay(2000);
  
  tft.print ( thermocouple1.readCelsius());
  Serial.print("C = ");
  Serial.println(thermocouple1.readCelsius());





}

Idahowalker · September 15, 2021, 4:36pm

Hey, thanks for trimming the code down.

as an fyi, use a higher speed.

Idahowalker · September 15, 2021, 4:39pm

I doubt it will make a difference but...

foccacia · September 15, 2021, 4:39pm

Idahowalker · September 15, 2021, 4:41pm

If they worked individually but not together, I'd put the TC on the other SPI buss.

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Node32s connect with tft and max6635

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