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Hi Pete,
As others have noted, the 1K sips with be fine but I had the same question last year so I asked the hardware designer John Monahan on the S100computers.com website hardware forum and below are the details. I couldn't figure how to link directly so I copied/edited/pasted the important details. ---------------------------------------------------------------------------------------------- Unregistered user (Guest) Username: Posted on Tuesday, May 08, 2012 - 9:49 am: Hi
John & All,
I've got my blank z80 PCB with me and have looked at the
schematics & have
a quick question regarding the use of 1.1k resistor SIPs for
RR2, RR3 &
RR4. It looks like a simple pull up for the inputs to the shift
register so I
am wondering why 1.1k and not 1k. The reason I am asking is I
have lots of 1K SIPs
but no 1.1K SIPs and the 1.1K SIPS seemed to be harder to find.
I assume there
is a reason these were chosen so I wanted to find out the
reason. ------------------------------------------------------------------------------------------------
John Monahan Posted on Tuesday, May 08, 2012 - 9:51 pm: Hi Jeff, definitely you can use 1K's. There seems to be some tradition going way back as to what pull-up’s should be. I've seen 1K, 1.1K, 1.2K even 2K and 5K. You are balancing noise immunity against total board power needed -----------------------------------------------------------------------------------------------
Jeff Galinat (Jgaliant) Posted
on Thursday, May 10, 2012 - 1:49 am :
Jeff On 4/7/2013 2:20 AM, Pete Plank wrote: Hello, I'm trying to put together the Z80 CPU board and ran into an issue regarding the 1.1K bussed resistor networks -- I can't find them in stock anywhere (eBay, Mouser, Digikey, etc.). I believe a compatible part number is Bourns 4610X-101-112. I need 3 of these -- anyone know of a source or have some extra they'd be willing to sell? Thanks much, Pete Plank |