iversion that runs without races - but not "perfect" code - needs spinlock instead...
converted scheduling to spin-lock to make it generic...
inew version with some TX transfers
inewer version with now takes less transfers and also is able to send
there is still something wromng, so that the buffer filles up...
partially working version of TX
problem is that after 0x16e packets the transfer is "stuck" and does not resume for cangen
wonder what is the reason (after a kill and restart it works again)
working TX code for the mcp2515a
only remaining issue is the error packet handling...