ODROID XU4 SPI shifter shield problems

Post Reply
Lawrence_0
Posts: 2
Joined: Fri Sep 13, 2019 1:16 pm
languages_spoken: english
ODROIDs: ODROID XU4 owner
Has thanked: 0
Been thanked: 0
Contact:

ODROID XU4 SPI shifter shield problems

Unread post by Lawrence_0 » Fri Sep 13, 2019 10:05 pm

I bought an odroid XU4 for SPI use. I was not aware of the 1.8V level as I hadn't checked beforehand.
I now need to interface with a 5V SPI device. The problem is that I bought the shifter shield as well, but the shifter shield IC's bug out and generate immense white noise.
This is a very big problem, its for university. The person next to me in the lab also has an XU4 and bought the IC's standalone and they produce the same effect as those fully installed on the shield.
Is there any way to mitigate this?

Lawrence_0
Posts: 2
Joined: Fri Sep 13, 2019 1:16 pm
languages_spoken: english
ODROIDs: ODROID XU4 owner
Has thanked: 0
Been thanked: 0
Contact:

Re: ODROID XU4 SPI shifter shield problems

Unread post by Lawrence_0 » Fri Sep 13, 2019 10:41 pm

If I run the DotMatrix example code, signals are generated. I'll focus on the clock.
Oscilloscope shows an almost perfect sine wave with a frequency of 50MHz, regardless of the SPI clock frequency that I alter in the code.
Even if no clock is generated. The level of this sine is between 1 and 2.2V.

User avatar
odroid
Site Admin
Posts: 32104
Joined: Fri Feb 22, 2013 11:14 pm
languages_spoken: English
ODROIDs: ODROID
Has thanked: 115 times
Been thanked: 287 times
Contact:

Re: ODROID XU4 SPI shifter shield problems

Unread post by odroid » Mon Sep 16, 2019 3:56 pm

As described in this wiki page, the level shift IC TXS0108E has poor driving capability.
https://wiki.odroid.com/accessory/add-o ... ift_shield

A few BSS138 MOSFETs must be much better for your application.
https://wiki.odroid.com/odroid-xu4/appl ... gpio/1wire
https://www.hardkernel.com/shop/level-s ... v-to-3-3v/

BTW, which SPI device do you want to connect to XU4?

Post Reply

Return to “Issues”

Who is online

Users browsing this forum: No registered users and 1 guest