COM port on ZX-Spectrum

[Tuesday 5 September 2000] at [01:30:06] Kirill Frolov wrote a letter to Felix
Knajzev.
They discussed the topic “COM port on the ZX-Spectrum”. Let's continue what we started...

FK>> 3. MS BB51 “does not maintain” the frequency of the Speck bus (believe me, this
FK>> happens when
FK>> crossing the domestic series KR580 with Speck)

KF> There you need to try to make a delay of RD and WR
KF> relative to CS,
KF> only for this microcircuits.

This is where the shamanism begins. Usually it's only the RD that has problems. For VI53 you even
have to play with the supply voltage (+5V).

FK>> =============== here we will finish the file "K580BB51.t"
FK>> ================

KF> This crap doesn't work on more than 9600 and is not compatible with anything
KF>.

By It is fully compatible with RS232 input-output; it is not used in bourgeois offtopics because of the significant difference in programming from other UARTs.

KF> Multikarta is cheaper.

It has higher efficiency. :) From connection to use. But in fact, if you don’t
chase speed and have an easily programmable MS UART, then BB51 will do.

Sincerely, Felix.

[I ZX]