Does anyone have the pinout for this LCD/

donperryjm

Well-known member
waveshare 3.5 rpi LCD (B)

I cant find the pinout for the header anywhere. It's an ili9394 IPS based LCD.
ee47665e-bab7-4cf4-b351-5afbd1652519.jpg
 
Well the 2 pairs of 13 pins tells me the board is likely designed for an original Raspberry Pi (later model Raspberry Pis now have 2 rows of 20 pins, but the first 13 pins are the same pinout as the previous pi models).

If you do a goggle search for 'Waveshare SpotPear' you will get to the Waveshare wiki for the display: https://www.waveshare.com/wiki/3.5inch_RPi_LCD_(A).

From that table the pins are:
  • Use one of the ground pins (6, 9, 14. 20 or 25) to hook to Teensy ground
  • Use one of the 3.3v pins (1 or 17) to hook to Teensy 3.3v
  • It may need 5v power, so connect the 5v pins (2 or 4) to Teensy VIN.
  • Pin 18 is command/register select (normally called DC or D/C in the Arduino world), hook to whatever your DC pin is
  • Pin 19 is MOSI, hook to Teensy pin 11
  • Pin 21 is MISO, hook to Teensy pin 12 (only used for touch input)
  • Pin 22 is the reset pin, attach to whatever pin you are using for reset
  • Pin 23 is SCLK, hook to Teensy pin 13
  • Pin 24 is the CS pin for the display
  • Pin 26 is the CS pin for the touch screen

The pins are odd pins on the left, even pins on the right.
 
Rather use https://www.waveshare.com/wiki/3.5inch_RPi_LCD_(B) (rev 1 not rev 2)
or use https://www.waveshare.com/3.2inch-RPi-LCD-B.htm if yours really is is 320x240 (ILI9341) and not 480x320 (probably ILI9486)

For Teensy36 I used the very similar 3.2 inch ILI9341 display like this
t36.jpg

For the Waveshare 3.5" Type (B) revision 2 LCD and Teensy36 I used:
t36b.jpg
which was only semi-working
LCD35inch(B)rev2-Teensy36 (2).jpg

Note that https://github.com/Bodmer/TFT_eSPI provides drivers for the 480x320 LCD(B) (tested as working with RP2040) and reported working with Teensy3x and 4x)
 
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(Maybe) ignore my comment on the LCD(A) wiki because:

3.5inch RPi LCD (A) and 3.5inch RPi LCD (B) (revision 1?) are hardware compatible with each other (use different drivers), and can be mutually substituted in most cases. (A) is the low cost version while (B) is higher quality IPS version with better display. This is (B) version.

https://www.kanda.com/products/Waveshare/SPI-3-5INCH.html
 
I am wondering if this display has a display driver chip on it or if it might be something like the KeDei display we were playing with a few years ago.
Which was another RPI 3.5" display, but it did not do standard SPI or the like but sort of. It hooked up shift registers, that you had to send so many bytes and control the CS register... We talked about it in the thread:

https://forum.pjrc.com/threads/5573...3-x-and-beyond?p=210170&viewfull=1#post210170

And I still have a repository for it, that has no promises.
https://github.com/KurtE/KeDeiRPI35_t3

It only got as far as it did as a couple of us were curious and too stubborn to give up ;)
 
From the eSPI config file:
The ILI9486 RPi display must be of the Waveshare design and use a 16 bit serial interface based on the 74HC04, 74HC4040 and 2 x 74HC4094 logic chips
The OP pic shows them all in an L shaped row on the PCB...
 
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