Stabilise and improve UART protocol
kanflo opened this issue · comments
There are a few design flaws in the current UART upgrade protocol and the use thereof, as mentioned in #191
dpsctl.pydoes not do do retransmits- As there are no counters in the
CMD_UPGRADE_DATAframes, a resent frame might result indevice reported CRC errorat the end of the upgrade process.
As this leads to changing the boot loader, the following should be added while at it:
- There should be protocol support to change the baud rate.
- Backwards compatibility should be kept (old/new
dpsctlshould be able to upgrade new/old dpsboot for all permutations of 'old' and 'new').
I guess a new CMD_UPGRADE_DATA2 frame is needed with a counter and dpsctl could start with this one and fall back to CMD_UPGRADE_DATA. The silly thing is that the boot loader does not NAK frames with unknown commands meaning we will need to throw a handful of CMD_UPGRADE_DATA2 at the DPS before falling back the old protocol. Gah!
A boot loader upgrade method should be implemented too for the brave out there.
It is really a good idea to have some kind of handshake dialogue for the bootloader and to repeat a broken frame. I found (#191) that the device just breaks at some point in communication where the GUI is still running. But I am not quite sure if this is always the same behaviour. I will try to verify this tomorrow.
BTW has opendps ability to set device address in the serial protocol... I believe that original firmware allows to use multiple devices on single serial line (= they only TX when queried by specific address)
Any updates on this? I cannot upload firmware due to Error: device reported CRC error.