Good idea, I'll give that a try!  Hopefully my Mouser order will arrive 
tomorrow as well....

- Gary

On Wednesday, August 27, 2014 11:56:16 PM UTC-4, monahanz wrote:
>
> See if you get the exact symptoms by switching around identical LS541’ s, 
> LS244, etc.  Often that can identify a bad one. Be very careful not to mix 
> the current working arrangement. I usually number them before any moves.
>
>  
>
> John
>
>  
>
>  
>
> *From:* [email protected] <javascript:> [mailto:
> [email protected] <javascript:>] *On Behalf Of *[email protected] 
> <javascript:>
> *Sent:* Wednesday, August 27, 2014 8:09 PM
> *To:* [email protected] <javascript:>
> *Cc:* [email protected] <javascript:>
> *Subject:* Re: [N8VEM-S100:5064] 6502 CPU board questions
>
>  
>
> John -
>
> Thanks for the hints.
>
> I'm able to input the IOBYTE correctly and echo to the screen.  The 
> monitor recognizes keyboard input and echoes them, just doesn't process 
> correctly.  I think it's a problem accessing RAM, as the symptoms are 
> slightly different with various ram boards - probably upper address line as 
> the I/O ports work fine.
>
> I have another batch of 74LS541's ordered, if that doesn't help I go thru 
> the board wiring again!
>
> - Gary
>
>
>
> On Wednesday, August 27, 2014 6:09:47 PM UTC-4, monahanz wrote:
>
> Gary do you have all the jumpers as listed in the yellow table in the 
> “normal” positions.  .  The fact that it can sign means you are almost 
> there.  Sounds like an address line problem or data I/O problem.  After the 
> signon have it input the SMB IOBYTE port and immediately output to console 
> in a loop. Check ASCII character is always correct.
>
> Next do same inputting from Propeller input port.  Next input, place in 
> RAM, read back from RAM and display… 
>
>  
>
> John
>
>  
>
>  
>
> *From:* [email protected] [mailto:[email protected]] *On 
> Behalf Of *[email protected]
> *Sent:* Wednesday, August 27, 2014 12:43 PM
> *To:* [email protected]
> *Subject:* [N8VEM-S100:5058] 6502 CPU board questions
>
>  
>
> I'm trying to get the 6502 Master/Slave CPU board working - and seem to 
> have hit an dead end.
>
> If anyone could confirm what they are using for monitor code, and jumper 
> settings I'd be VERY appreciative!
>
> Background:
>
> Minimal system with SMB, 4mb SRAM, Propeller I/O and 6502 most recent 
> Master/Slave PCB.  The SMB, SRAM and Propeller boards work fine with Z80 
> and 8088 systems.
>
> All testing and assembly worked as expected following John's notes until 
> the 28C64 was installed.
>
> I burned the 28C64 from the 6502mon.bin V1.0 file, with the code starting 
> at 01000H in the 0000H --> 1FFFH space.  01000H thru 010FFH contains 00h as 
> expected, and I can see the jump vector addresses in the top of memory.  
> 0000H thru 0FFFH contain FFH as a fill character.
>
> I had to change the P31 jumper to connect 5-6 to get the monitor to sign 
> on.  Set up as a bus master (only cpu in system).
>
> Now I get the monitor to sign on and print the menu twice.  It then 
> accepts input characters but doesn't respond properly to any.  Single 
> letter commands like "A" just reprint the menu.  Longer commands like 
> D0000,0100 accept the full input and reprint the menu.  
>
> CPU is a W65C02S6TPG-14 purchased thru a reliable source (Mouser) - and I 
> have a second CPU (same source/batch) I've also tried.  I've replaced every 
> other IC except the 74LS541's (I only have a single spare - which I've 
> substituted for every position).  I've resoldered ever connection.  I've 
> tried both 28C64 and 27C64's for the monitor.
>
> - Gary
>
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