How to drive manually HT1621B LCD driver IC? - Page 1
Forum section: electronics / general

author: q12
author_rank: Contributor
timestamp: December 20, 2024, 07:30:55 am
content: - Im trying to figure out how to drive (manually-bitbang) aHT1621BLCD driver IC. It is capable of driving multiplexed LCDs. They are very cheap, but only in smd form, which is a bit of a challenge to solder all its tiny 48 pins. Seehttps://youtu.be/xwRXpbxjLcw- you can skip through the movie since it's a long one. I actually managed to drive them using a special library in arduino, and they work beautifully but...I want manual drive. Why? because I can use only logic ICs like nand gates,multiplexers, FF's, etc 40 and 74 series, and also my favorite very easy to drive 12F508 PIC, and why not even an EEPROM. And I can also add custom characters or shapes or symbols.- I read their datasheet a couple of times and STILL, I can not decipher the real way of driving them. I also find 2 AN's (AppNotes) AN2343-Cypress and AN0468e HT162x Application Guidelines -HOLTEK. They helped a little but not completely.- Here is a list with all my LCD movies I made so far:https://www.youtube.com/playlist?list=PL6NJF1kQFOAI0-AstwH5YHuOHenjLtkbS,including this HT1621B IC. Again, skip through their content since Im showing you what I tried and how high I could reach.Thank you very much.

author: xvr
author_rank: Frequent Contributor
timestamp: December 20, 2024, 11:51:31 am
content: QuoteDid you see timing diagrams on page 7? It is a quite clean way to interface to HT1621

author: q12
author_rank: Contributor
timestamp: December 20, 2024, 12:05:21 pm
content: Please write down what to try.Im bitbanging using arduino uno R3 board, with direct wire links to the IC pins.I have no idea how to resize this image, to make it smaller than this.So this is a working setup, that is usinglcd.begin(0, 2, 3); // (cs=0, wr=2, Data=3)where, cs=0 means that IC cs pin is linked to pin0 on arduino. , The same logic applies for the other pins.in the arduino code + library.Im using a test program to reassure everything is connected and working correctly.Next is to actually find a way to bitbang this IC input pins. Those 3 mentioned.

author: xvr
author_rank: Frequent Contributor
timestamp: December 20, 2024, 12:29:04 pm
content: You should look inside Arduino Library. All interfacing implemented there.Or implement diagrams from blank page - from page 7 of datasheet.Initial state: CS is 1, WR in 1Write cycle:Set CS in 0For each bit of output:Set Data to desired valueSet WR to 0Set WR to 1RepeatSet CS to 1

author: q12
author_rank: Contributor
timestamp: December 20, 2024, 02:44:33 pm
content: If it helps, these are the 5 links in the image://HT1621B pin = Arduino pin//cs=0, wr=2, dt=3, rd=1,irq=4https://forum.allaboutcircuits.com/attachments/ht1621b-pin-assignment-jpg.338524/The red links in the image, were the easy wiring I made the first thing after I soldered the IC.The harder links are the cyan ones that needs programming data.

author: q12
author_rank: Contributor
timestamp: December 22, 2024, 11:31:28 am
content: I managed to make it work !!!If you want to see some awesome code and some advanced programming discussion, then check this link:https://forum.arduino.cc/t/how-to-drive-manually-ht1621b-lcd-driver-ic/1334073/54

author: q12
author_rank: Contributor
timestamp: December 22, 2024, 10:05:44 pm
content: https://youtu.be/FuVLCtCjlbw