Newhaven Display Forum

Newhaven Products => Character LCDs => Topic started by: VATH on June 13, 2018, 10:41:46 AM

Title: NHD-0420D3Z-NSW-BBW-V3_revB has strange behavior through SPI with Raspberry Pi
Post by: VATH on June 13, 2018, 10:41:46 AM
I'm trying to send commands and characters to the LCD Screen, and instead of recognizing any of the data coming through via SPI, the screen just prints out the same character that doesn't match any form in the datasheet. This printout happens for every byte that is sent from the Pi to the LCD.

On the oscilloscope and other signal analysis tools, the data looks fine. Our clock speed is under 10kHz, there is definitely data being sent from MOSI, and the chip enable matches up.

I suspect this is some kind of timing issue but we can't seem to figure it out. We're currently using the bcm2835 library for SPI. This problem persists for both a Raspberry Pi Zero W and a Raspberry Pi 3B.

Here is a picture of the LCD Screen characters: https://drive.google.com/open?id=1NL5L29cRPE3PIjEKbWjCc4p9CLdEgsyQ (https://drive.google.com/open?id=1NL5L29cRPE3PIjEKbWjCc4p9CLdEgsyQ)