ZodiusInfuser
Member
Hi,
I've been working for the past months on adapter PCBs that convert Teensy 3x and 4x to the Pi Zero form-factor, offering an alternative to a Raspberry Pi for those projects that really do not need an OS running in the background.
I'm close to done with the design and routing now, but there's a few things on the pinout that I am double checking with some Adafruit perma-proto boards I soldered up.
Testing has been going fairly well (here's a clip of an SPI LCD test: https://twitter.com/ZodiusInfuser/status/1268547125455073280?s=20), however, when I attempt to use I2S in conjunction, the SPI no longer works.
I've narrowed the problem down to MOSI and MCLK sharing the same pin on the 3.x. Now I can get around this by switching MOSI to its alternate pin so the function's no longer conflict, but that's just shifting the problem to another pin that could still cause issues with some Pi HAT combinations. So instead of that, is there a function I could call, or register parameter I could change to disable the MCLK outputs outright on all T3x and T4x boards? The Pi GPIO header does not have MCLK exposed, so it is an unneeded clock signal for any I2S audio HATs. Sadly I cannot just leave the pin disconnected, as I'm two pins short of a full mapping on the smaller Teensy boards if underside pins aren't soldered to (an option I want to keep open to people).
If it is not possible to disable MCLK then I will adjust my routing to use the alternate MOSI pin, but thought I would put the question out there.
Thanks in advance
I've been working for the past months on adapter PCBs that convert Teensy 3x and 4x to the Pi Zero form-factor, offering an alternative to a Raspberry Pi for those projects that really do not need an OS running in the background.
I'm close to done with the design and routing now, but there's a few things on the pinout that I am double checking with some Adafruit perma-proto boards I soldered up.
Testing has been going fairly well (here's a clip of an SPI LCD test: https://twitter.com/ZodiusInfuser/status/1268547125455073280?s=20), however, when I attempt to use I2S in conjunction, the SPI no longer works.
I've narrowed the problem down to MOSI and MCLK sharing the same pin on the 3.x. Now I can get around this by switching MOSI to its alternate pin so the function's no longer conflict, but that's just shifting the problem to another pin that could still cause issues with some Pi HAT combinations. So instead of that, is there a function I could call, or register parameter I could change to disable the MCLK outputs outright on all T3x and T4x boards? The Pi GPIO header does not have MCLK exposed, so it is an unneeded clock signal for any I2S audio HATs. Sadly I cannot just leave the pin disconnected, as I'm two pins short of a full mapping on the smaller Teensy boards if underside pins aren't soldered to (an option I want to keep open to people).
If it is not possible to disable MCLK then I will adjust my routing to use the alternate MOSI pin, but thought I would put the question out there.
Thanks in advance