Xinyuan-LilyGO/TTGO-T-Display

Which PINS are free to use for another SPI device?

minkione opened this issue · 9 comments

minkione commented

Hi,
Which pins are still free from the TFT in order to be connected to another SPI device?

minkione commented

thanks! Will give it a try.
Quick question, since I will need also 2 more free spare GPIOs...
Which are the GPIOs that can still be used overall?

JoeBarouneD commented

You can use almost all other GPIOs.
Have a look at the Pinmap. Many GPIOs are free.

minkione commented

I am asking because respect the usual ESP32 the pinouts for SPI doesn't look the same.
image

Versus the T-Display... (marked in red the pins in scope)
image

minkione commented

Here I am comparing the ESP32 pinout and the pinouts from the T-Display schematics.
Now makes everything more clear. Though a doubt still remain regarding VSPI and HSPI... how do you enable the VirtualSPI (VSPI)? Just connect the device to those Pins and then declare in the sketch and everything works?

image

flyandi commented

HSPI is only on 27,26,25 (MOSI, MISO, SCLK) - at least from my experimentation .. CS pin can be anything.
VSPI can be on any free pin..

siriokds commented

I used this for sd card access.

SPIClass spiSD(HSPI);

pinMode(2, OUTPUT);
spiSD.begin(13,12,15,2); //SCK,MISO,MOSI,SS

raomin commented

I wanted to connect a second display (ILI9341) on a secondary SPI.
While 27,26,25 (MOSI, MISO, SCLK) and 33 CS is ok, I found out that the pins 37 38 39 do not work for DC (Data command), RST (Reset) (or CS...)
Pins on the other side (17,2,15,12) works for DC, RST etc.

I ended up with:

#define ILI9341_DRIVER

#define USE_HSPI_PORT
#define TFT_MISO  27  
#define TFT_MOSI  26  
#define TFT_SCLK   25 
#define TFT_CS    2

#define TFT_DC   33  // Data Command control pin
#define TFT_RST  32  // Reset pin (could connect to NodeMCU RST, see next line)
lockie555 commented

I am having an issue with using 3 devices (SD, 9341TFT, & RM3100) on SPI on a TTGO-T4v1.3.
My code works fine on a STM32 Nucleo152 but I cannot get the SPI bus to work on the T4. As the SD and TFT are built in on the T4, I only have access to the jumper pins and I chose SCLK-32; MISO -35; MOSI-34; CS-33 for my RM3100 magnetometer sensor.
The documentation re SPI on the T4 is a bit lacking, and I assume the SD and the TFT are both on default VSPI. I have tried the RM3100 as a HSPI but got nowhere; nor does it work as a VSPI. The TTGO-T4 pinout diagrams show the SD using SCLK -14, MISO-02, MOSI-15, CS-13 which are not the HSPI defaults and the TFT using SCLK -18, MISO-12, MOSI-23, CS-27 which are not VSPI defaults.
I tried LewisXHE's code for SD with the TTGO-T display and had no luck with that either. I am not sure whether the problem is a lack of understanding by me. I learn by example and I haven't been able to find any examples of external sensors using SPI on T4. Any ideas?