6 Feb
2006
6 Feb
'06
8:42 a.m.
On 2/6/06, 9000 VAX <vax9000 at gmail.com> wrote:
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.
On the REV.0 board I used 74LS14 to receive critical lines (DIN, DOUT,
RPLY...), and plain LSTTL for other non critical lines (DAL0-22, WTBT,
BS7...) and it worked OK too.
vax, 9000