TV Hat (and ControlBlock?)
Forums:
Hi there
I'm wondering if I can use this to enable the usage of the official Pi TV uHat and the PetrockBlock ControlBlock.
I've checked the GPIO pin-outs here:
https://www.raspberrypi.org/forums/viewtopic.php?t=235171
... and I'm afraid that I was left a little more confused than when I entered. Some folks indicate that this page shows the pins used by the TV Hat:
https://github.com/raspberrypi/linux/blob/4c5aec7827ac970729ac54e57cbd85...
However, there's nothing there which looks obvious to me ... I am a bit inexperienced, though. ;-)
Additionally, I have sent an email to PetrockBlock, because looking at their site for the ControlBlock it does say:
"All 32 GPIO channels of the ControlBlocks can accessed via SPI and, thus, can also be used for any other purpose for your project!"
https://www.petrockblock.com/controlblock/
... plus it seems to allow stacking, so maybe I can just use it without the TriBorg?
I dunno, which (I guess) is why I'm here! Heh.
Not asking any of this with any odd entitlement to an answer, but if you have thoughts and/or ideas of a way forward I'd be most grateful.
Cheers.
Eliot
piborg
Tue, 11/24/2020 - 10:55
Permalink
Maybe, depends on the PetrockBlock
I have had a look and the answer is maybe, it depends on what the PetrockBlock is capable of.
So both boards use the pins for SPI. This is fine because SPI is designed so that multiple chips / boards can share the same connections to communicate. So far this would be fine with a TriBorg+ or stacking.
The problem is that SPI uses another pin, called a chip select, to signal which board it is currently talking to. The TV Hat uses CE0 (pin 24 on the connector) for this. Unfortunately my guess is that the PetrockBlock uses the same pin :(
If it is possible to get the PetrockBlock to use CE1 (pin 26 on the connector) instead then they can share the SPI correctly.
For reference these are the GPIO pins for SPI: https://pinout.xyz/pinout/spi
Both boards are using SPI0 in this case.