Hi Mike,
Thanks for the reply. I already have a datasheet for the Z80 SIO 8440.
Would that be a similar match for the DART or would your datasheet be
nearer the mark?
I don't have the mapping from Zilog numbers to Mostek ones, so 8440
means little to me, however I believe that if you already have the SIO
datasheet then you effectively have the DART datasheet. As far as I
recall, the DART datasheet (a single page?) just said something like
"The DART is a reduced function version of the SIO in which only async
modes are supported."
Does your SIO datasheet explain the three different pinouts available?
The only remaining question I think is which of the three SIO pinout
options was used for the DART. The difference lies in the port B signals,
one pinout omitted SYNCB, one omitted DTRB, the third connected TxCB
and RxCB to the same pin. I'm 100% sure DTRB was implemented on the
DART, so it chose either to omit SYNCB or share the clocks. So it's
either 29=RxDB 28=RxCB 27=TxCB or 29=SYNCB 28=RxDB 27=RxTxCB.
How long is your SIO datasheet? Is it sufficient for your needs?
Regards,
Mike.