Busy Light?

[walter_J64bit]

Ok is there a mod for the RAMBO XL where I can add a Busy Light to it so I see when it's in use?

Edited May 15, 2007 by walter_J64bit

[Rybags]

Is it possible?

 

Such a scheme would probably also pick up the automatic refresh which Antic provides.

[classics]

Isn't PB4 always low for extended ram access?

 

If so just connect PB4 to an inverter gate, the output to a 120ohm resistor and through a LED to ground.

 

Steve

[Mathy]

Hello Steve

 

On the 130XE as well as on my own XEGS with 1MB, either PB4 or PB5 is low when extended memory is used.

 

BTW a schematic for an "Extended Memory being accessed" LED (which IIRC only checks for PB4) should be on the net somewhere. I've seen it, but it was a long time ago.

 

Greetings

 

Mathy

 

PS to test both PB4 and PB5 you only need to replace your inverter by a NOR-gate and use both signals as input.

Edited May 15, 2007 by Mathy

[+bf2k+]

Ok is there a mod for the RAMBO XL where I can add a Busy Light to it so I see when it's in use?

 

I know I have seen one but I don't remember where...

[walter_J64bit]

Oh, did say I 1200XL so "PB4 or PB5" is what I need to look for on the 1200XL motherboard?

[Mathy]

Hello Walter

 

IIRC it's pin 14 and 15 on the PIA chip.

 

Greetings

 

Mathy