metall0r
Posts: 1
Joined: Sun Sep 16, 2018 9:08 am

CM3 sending RS232 Signals to base board

Sun Sep 16, 2018 9:23 am

Hi at all,

i have a special base board driven by a CM3 module where i can attach a display. So it's a combination of a Raspberry CM3 driven Mediaplayer and an LVDS controller. I would like to use it as a digital signage solution.

I'm now looking for a way to set the scaler chip to status "off" when there is 0V on the GPIO4 and to status "On" when there is 3.3V on the GPIO4.

The calls i have to make are as follows:
08 34 3F 02 00 00 FF 84 (Switch scaler to Power Off Mode)
08 34 3F 02 00 01 FF 83 (Switch scaler to Operating Mode)

As i don't use a external RS232-Cable i have to send the Signals from the CM3 to the base board.

On my research for a solution i've only found discussions where a RS232 Cable/Connector was used and that's not the case here.

The manual of the base board can be found here:

https://www.displaytechnology.co.uk/ass ... t_spec.pdf


Thank you in advance for thinking it through and maybe having an idea.

Kind regards

aBUGSworstnightmare
Posts: 1097
Joined: Tue Jun 30, 2015 1:35 pm

Re: CM3 sending RS232 Signals to base board

Sun Sep 16, 2018 6:26 pm

It's in the document you've linked:
Two UARTs connect to the Compute Module via an USB-to-UART bridge
why can't you use UART2/3 for this?

PhilE
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 1904
Joined: Mon Sep 29, 2014 1:07 pm
Location: Cambridge

Re: CM3 sending RS232 Signals to base board

Sun Sep 16, 2018 8:28 pm

This sounds like a fairly common question that would be better addressed to the supplier/manufacturer of the base board.

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