The general idea is to keep platform specific implementation away from the MMU state machines as much as we can.
That would enable unit testing the top level MMU state machine and integration into other project as well (if needed).
This is a prototype implementation of having the ability to show an MMU error screen even for printer's errors (during an MMU operation).
Also, the retry count of unloads after failed load the extruder tube is now limited to ~3 attempts.
Technically, since this very error is not an MMU's one (MMU is just fine at this stage) but a printer's one I tried to hack the existing error-reporting infrastructure to handle such a case.
The original idea of this approach was suggested by @vintagePC
In Idle and Command mode it is now possible to specify a list of registers which shall be periodically read from the MMU.
To keep the code and RAM size down registers are intentionally separated into 8bit and 16bit sets.
Adding a register into the set is just a matter of parametrization, there is no need to change the state machines anymore.
Because it looks like the communication drop outs are caused by some electrical issues and we can loose even a byte from the version response, which is deadly for future operation.
Communication timeout and Protocol Errors are now distinguished.
In case of a Protocol Error, the printer waits for heartBeatTimeout to allow filling up the input UART buffer (we expect the MMU still produces some bytes).
Once the timeout elapsed, the input UART buffer is cleared and a new Start Sequence is initiated.
Guðni Már Gilbert
D.R.racer
DRracer
Yuri D'Elia
VintagePC