Hi,
I am in the process on creating a custom board for driving a configuration of two 32x64 panels with a Teensy 4.1. I also wanted to access I2S audio output and input for the project.
I made a (rather hurried) first version of the design, but the screen does not light up at all. I had essentially remapped all the pins to other locations (included below) and upon some deeper reading its looking like that wasn’t the best idea.
As it looks like I will probably need to do a redesign, I just wanted to check first. Are the pins mapped in the Teensy 4 V5 board critically placed, or is there scope for remapping? Is this based off a FlexIO configuration? Sorry if this is written in the documentation/forums somewhere, but I’ve not seen it around.
Thanks in advance, any help would be greatly appreciated!
It’s probably not well documented, but the pins are very critically placed, and there’s little option for remapping. There’s no way to use the I2S input/output pins (pins 7/8) simultaneously, that’s why the jumper was added. I don’t think those signals are available on other pins, though maybe they are on the back or on the extra 4.1 pins. Check the wiki and the schematic for some more documentation, and maybe you can ask @easone who did the Teensy 4.1 port either here on on the PJRC forum for more details, as I don’t know a ton about FlexIO
There is some limited room to change pins when designing a custom board, but there are restrictions relating to FlexIO and FlexPWM.
In fact it is possible to have both I2S input and output available if you are using T4.1, it just wasn’t possible to do this and keep it compatible with T4.0 (without needing to solder to the bottom pads, that is)…
Any of the pin configurations in this Google Sheets document should work, although I certainly haven’t tested them all. The I2S capability is listed under the column “Audio Shield”.
Thanks to you both for getting back to me - I’m super grateful for your time and effort!
That spreadsheet is awesome, thanks @easone! I’ll check it out in more detail and see what requires the least amount of change from what I have currently mapped. Might be time to get Frankensteiny!
I used the spreadsheet of awesomeness and honed it down to the most convenient row, given my needs. I cut some traces and soldered some wires about the place on my board, updated the pin mapping in my test firmware and Bam! Worked first go!
This gives me some solid direction for the redesign and a prototype to test with in the meantime.
Thanks again for your help guys! I really appreciate it.
Glad it worked!
Hopefully the spreadsheet will be useful in the future. For example, if someone wanted to have SPI available, there is a custom configuration in there that should work.
