UNIBUS transceiver was RE: have an extra M105 + M7821 unibus card?

9000 VAX vax9000 at gmail.com
Mon Feb 6 10:39:27 CST 2006

On 2/6/06, Don North <ak6dn at mindspring.com> wrote:

> It's not clear from the above discussion from 9000vax as to what he used
> for the bus receiver; he just describes using the 7406 as an output
> driver on QBUS. Not clear what he uses on input.

I use ALTERA EPM1270 CPLD to receive QBUS directly. It has 4V absolute
max input level but I can enable the internal diode to limit the
possible voltage surge (in PCI pin compatible mode). I set the input
level to 3.3V LVTTL for a time and it worked OK too.

vax, 9000

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