m_thompson
Veteran Member
Mal,
The initial problems with Vince's board was in the bus interface ICs. The initial choice of 74ABT540 caused too much ringing on the Omnibus, and a 74LS540 replacement worked much better.It would be interesting to see if your CPLD is driving the Omnibus as hard as the 74ABT540 was and is causing ringing.
The initial problems with Vince's board was in the bus interface ICs. The initial choice of 74ABT540 caused too much ringing on the Omnibus, and a 74LS540 replacement worked much better.It would be interesting to see if your CPLD is driving the Omnibus as hard as the 74ABT540 was and is causing ringing.