Hi,

Crikey, it's been a long time since I posted here. Life has been hectic and I haven't been able to get back to my old processor systems for sometime, but hopefully this will soon change.

In regards to my AIM-65s - I modified one of them to provide extra capacity. It now has 40k RAM (1 x 32k ...

Hi,

I have removed the on-board 4K RAM of the AIM65, and all RAM is now with the 32K (62256) chip, which is part of the expansion I am building. The system boots and I ran some memory tests to prove its okay.

The AIM monitor memory and IO devices and ROMs reside in address range A000-FFFF.

Hey ...

Hi,

Yes, I got the point..... finally.

As I am adding components within the address range of 0000h to 9fffh, I must ensure that the 245 is enabled only when this address range is active. Outside of this range is the on-board AIM65 devices and therefore the 245 should be disabled when addressing ...

Hi,

I tried the invert PHI2, but to no avail. So, I just bridged the databus straight through and its working, so I'll see how it goes. I'd like to see a circuit of one, though.

rgds
Shane

Hi,
I'm trying to expand an AIM65 with some extra memory and IO. I am prototyping it on breadboard, which is connected to the AIM65 via its 44pin connector.

I am using a 74LS245 for the databus buffering, but the unit doesn't work with it connected. I tried a few other '245 chips and checked they ...