Looking for a character LCD - Page 1
Forum section: electronics / beginners

author: sam1275
author_rank: Frequent Contributor
timestamp: June 16, 2015, 08:52:52 am
content: Hi everyone.Is there any off-the-shelf LCD that support displaying characters DIRECTLY from UART serial signal? I mean the signal that comes out from the router/embedded device's serial 4-pin port, not the common LCD that require some addition driving method.Thank you.

author: bktemp
author_rank: Super Contributor
timestamp: June 16, 2015, 08:55:15 am
content: www.crystalfontz.commakes serial LCDs.Many VFDs also support a serial interface.

author: sam1275
author_rank: Frequent Contributor
timestamp: June 16, 2015, 09:01:44 am
content: Quote from: bktemp on June 16, 2015, 08:55:15 amThank you, but will they work if I connect them DIRECTLY to the UART output?

author: bktemp
author_rank: Super Contributor
timestamp: June 16, 2015, 09:09:01 am
content: Those LCDs support some often used baudrates like 9600, 19200 or 57600 baud. If your device supports one of them it will show the characters on the screen without any additional circuit.Most serial displays use the not so useful characters 0-31 for commands like positioning the cursor.If you want to display text without any formating (except for CR+LF) it will work.

author: sam1275
author_rank: Frequent Contributor
timestamp: June 16, 2015, 09:22:13 am
content: Quote from: bktemp on June 16, 2015, 09:09:01 amThank you very much !!!

author: sam1275
author_rank: Frequent Contributor
timestamp: June 16, 2015, 09:57:36 am
content: Quote from: bktemp on June 16, 2015, 09:09:01 amHello, will this OLED do the job?http://www.newhavendisplay.com/specs/NHD-0420DZW-AG5.pdf

author: H.O
author_rank: Frequent Contributor
timestamp: June 16, 2015, 10:20:37 am
content: No, the datasheet shows that serial interface on that display is synchronous, ie data is "clocked" into the device by a dedicated clock signal. Your UART output is asynchronous, ie there is no dedicated clock signal. Two different types of interface, not compatible with each other.If your device is a microcontroller the peripheral you're looking for in order to drive that displays serial interface is SSP/MSSP/SPI type of thing. Or you could obviously bitbang it.

author: tron9000
author_rank: Frequent Contributor
timestamp: June 16, 2015, 10:52:42 am
content: Matrix orbital do some RS232 LCD's -http://tron9000.blogspot.co.uk/2014/01/trash-find-screens-testing.htmlThese are some I slavaged, found out they could do RS232 and I2C

author: sam1275
author_rank: Frequent Contributor
timestamp: June 16, 2015, 11:32:50 am
content: Quote from: H.O on June 16, 2015, 10:20:37 amThank you, so I should looking for SPI ones? What about RS232?

author: bktemp
author_rank: Super Contributor
timestamp: June 16, 2015, 11:58:39 am
content: SPI ones will not work if you connect them to UART/RS232 without an additional microcontroller.

author: sam1275
author_rank: Frequent Contributor
timestamp: June 16, 2015, 12:53:23 pm
content: Quote from: bktemp on June 16, 2015, 11:58:39 amthanks.So stick to RS232 will be alright?

author: DJohn
author_rank: Regular Contributor
timestamp: June 16, 2015, 03:42:54 pm
content: Quote from: sam1275 on June 16, 2015, 12:53:23 pmMaybe, maybe not. It isn't clear whether you're talking about RS232, or logic-level asynchronous serial. The timings are all the same, but the voltages are very different. If it's connected directly to the pins of the UART chip, it's likely to be logic-level. If it's on a connector, there's a chance it's RS232 (but it might not be).There's no standard name for the logic-level version (this is just what I call it), and people often call both RS232. Before you go plugging displays into it, put a multimeter on the data line. If it's negative when idle, you've got RS232 (-12V is typical). If it's 3V or 5V or somewhere around there, it's logic-level.Newhaven have some displays that say "RS232 (TTL)", meaning logic-level. They would get very unhappy with real RS232. lcd-module.com have some that appear to take both (on different pins).

author: ElectricGuy
author_rank: Regular Contributor
timestamp: June 16, 2015, 03:53:27 pm
content: http://seetron.com/ilm216.html