Does nrf52840 support PS/2 protocol reading?

[nine-fox]

Hi, 

Since I saw nrf52840 is for "mouse, keyboard" in document, may I ask, is there any hardware supporting to read mouse PS/2 protocol?

If there isn't, any idea to read PS/2?

Thanks,

Vincent

[Håkon Alseth]

Hi,

 

The nRF5-devices normally act as wireless mouse or keyboards, via bluetooth LE or a proprietary protocol (with a small USB dongle containing nRF24LU1+, or nRF52840).

Note that nRF24LU1+ and nRF52840 are the two devices we have that has USB capabilities.

 

PS/2 is not supported, as the GPIO pads are not 5V compliant.

 

Kind regards,

Håkon

[nine-fox]

Hi Håkon, thanks a lot for your reply.

May I ask, if I can find a way to lower 5V to 3.3V, is there any idea to read PS2 protocol using GPIO?

Currently, I converted 5V to 3V and I can use GPIOTE with high accuracy mode to read DATA IO status for each PS2 CLK pulse. However, I just found, it will lose data when I turn BLE on. It works quite well without BLE. I think this data loss is due to BLE higher level interrupt.

Any idea to do reading under BLE without data lost? Thanks very much.

Vincent

[Håkon Alseth]

Hi,

 

Your best bet is to try to use one of the existing peripherals to capture/send the data so that it can handle the transport layer and buffering.

It looks like you could use the TWIM or TWIS (depending on if you are reading or writing data) based on the waveforms found in this article:

http://www.burtonsys.com/ps2_chapweske.htm

 

However, I just looked at this briefly, it might not work as intended.

 

Best regards,

Håkon

[nine-fox]

Hi Håkon,

Thanks for your suggestions. As far as I can see, the first byte in TWIS is the address. Since this address is assigned before I start TWIS, not sure how to read the first byte in PS/2.....anyway, I will have a try on TWIS. Thanks

Best regards,

Vincent