Hi all,
I have been using Teensy, and the Teensyduino libs, for a proof of concept device and the team I am working with have presented a couple of questions related to the ARM chip and pin modes. If someone could clarify some of these questions it would be greatly appreciated.
So far I have pointed them to “core_pins.h” in hopes that it will at least provide more context as to what is happening. Here are their questions:
Again, any help would be greatly appreciated and I really enjoy using Teensy for my projects! Thank you for your time.
Cheers,
Chase
I have been using Teensy, and the Teensyduino libs, for a proof of concept device and the team I am working with have presented a couple of questions related to the ARM chip and pin modes. If someone could clarify some of these questions it would be greatly appreciated.
So far I have pointed them to “core_pins.h” in hopes that it will at least provide more context as to what is happening. Here are their questions:
- In the ARM side there are pins name PTA0 to PTA19 and PTB0 to PTB19, PTC0 to PTC11, PTD0 to PTD11. These are multiplexed pins. There are multiple alternate definitions for those in the ARM manual. The port control module selects which mode the pins operate in (pages 207-210 in the K29P64M72SF1RM manual). I am guessing by looking at the table that the mode selected is ALT1.
- If we confirm it is ALT1, then it looks like all the pins are mapped as they are to the system. Somehow they need to be interpreted internally. Who does that?
- What happens to analog input pins in our design for example PTC1, PTC2. I would assume they need to be converted to digital through an ADC. But under the ALT1 mode there are no ADC connections. But these connections exist in other modes. But If you choose the other modes, there are different interfaces assigned to other pins like SPI, I2C, UART etc., which are not needed for the functionality of the buttons. So I would like to understand what mode and how these inputs into the pins are interpreted on the ARM/firmware side – Meaning what functionality are these pins actually performing on the ARM side?
Again, any help would be greatly appreciated and I really enjoy using Teensy for my projects! Thank you for your time.
Cheers,
Chase