quick slrom question

A place that you can discuss reproduction of classic titles or "licensed-for-reproduction" homebrew for personal use.

Moderators: B00daW, Moderators

Forum rules
1. NO BLATANT PIRACY. This includes reproducing homebrew less than 10 years old, with the exception of free software.
2. No advertising your reproductions, with the exception of free software.
3. Be nice. See RFC 1855 if you aren't sure what this means.
Post Reply
sleepy9090
Posts: 81
Joined: Fri Aug 22, 2008 10:04 am

quick slrom question

Post by sleepy9090 » Wed Dec 29, 2010 11:30 am

was working on making an slrom eprom cart and had a quick question

The info for making one explains:
SLROM (mapper 1):


PRG socket:
Bend up pins 1, 2, 24, 30 and 31 (or cut tracks)
Solder pin 2 to hole 24 (A16)
Solder pin 24 to GND (OE)
Solder pin 30 to hole 1 (A17)


CHR socket:
Bend up pins 1, 2, 22, 24, 30 and 31 (or cut tracks)
Solder pin 2 to hole 24 (A16)
Solder pin 22 to hole 31 (CE or CHR /A13)
Solder pin 24 to hole 2 (OE or CHR /RD)


these are for a 27CXXX series, when I compare the datasheet for one I notice that 27CXXX chip has 5V for pin 1

Why is pin 1 left floating? shouldn't it be tied down to 5V?

thanks

socram8888

Post by socram8888 » Thu Dec 30, 2010 7:53 am

You can leave it disconnected or tied anywhere: it's VPP and it won't do anything unless you put /WE down and connect that pin to >12,5V

sleepy9090
Posts: 81
Joined: Fri Aug 22, 2008 10:04 am

Post by sleepy9090 » Thu Dec 30, 2010 9:00 am

thanks for the info!

Post Reply