Newhaven Display Forum

Newhaven Products => Character LCDs => Topic started by: Chruetli on December 01, 2017, 02:40:04 PM

Title: NHD-C0220Biz-FS(RGB)-FBW-3VM initialization problem
Post by: Chruetli on December 01, 2017, 02:40:04 PM
I'm using an embedded Linux system - with a dedicated I2C bus - to drive a "NHD-C0220Biz-FS(RGB)-FBW-3VM" display. The Linux kernel module supplies an I2C master, so I do not have to bit bang.
Using 'i2c_master_send(...)' does the addressing, clocking and so on. Most calls work but 0x39 and 0x01 don't work...
0x0  -> ok
0x38 -> ok
0x39 -> fail
0x14 -> ok
...
0x0c -> ok
0x01 -> fail
...


I also tried to make 2 byte packets {0x0, 0x?} and send them together but the same commands failed. And there is no visible reaction on the display.
Any sugestins?
Title: Re: NHD-C0220Biz-FS(RGB)-FBW-3VM initialization problem
Post by: Chruetli on December 03, 2017, 02:59:51 AM
Hmm, just found out that my dev board has 2.2k pull-up on SCL and SDA lines - instead of 10k as recommended. But my logic analyzer show all commands as expected...
Title: Re: NHD-C0220Biz-FS(RGB)-FBW-3VM initialization problem
Post by: Saurabh_B on December 05, 2017, 08:15:02 AM
Are you sending a delay between the commands or allowing the commands that were sent to execute?
Title: Re: NHD-C0220Biz-FS(RGB)-FBW-3VM initialization problem
Post by: Chruetli on December 07, 2017, 07:18:41 PM
Solved, the 2.2k poll-up was the root of the evil. Removed from the demo board and replaced by an external 10k, all is doing right!! Those 10k are pretty important...
Title: Re: NHD-C0220Biz-FS(RGB)-FBW-3VM initialization problem
Post by: Paul_B on December 08, 2017, 07:52:14 AM
Glad to hear you got your display up and running!

Thanks for sharing your solution, it will definitely help others  :D