Cartridge connector signals
Posted: Sun Oct 10, 2010 7:22 pm
I'm wondering if anyone (Fonzie?) can elaborate on this forum about the cartridge connector signals which were discussed here:
http://segaxtreme.net/community/topic/1 ... -analysis/
There are a couple of things I'm curious about:
- How to detect a read from the /TIME area. Since it is only pulsed for reads and writes, I suppose checking for /LWR and /UWR inactive could be one way. But I wonder if one of the other read strobes like /CAS0 is valid in that range.
- Which signals on the cartridge connector change when /CART is pulled high, putting the system in Sega CD (floppy disk drive!) mode. In the linked thread patroclus02 answered some of this.
- Which signals become SMS signals in Mark-III mode. I gave up tracing a Power Base Converter, but I'm sure it would be easy to tell from a third party adapter (which may not hook up all the signals) or a Phantasy Star MD cart.
- Which signals are affected by enabling DRAM refresh mode in $A11000.
- In general what the purpose of the uncommon strobes are; nearly all games use /CE0 for ROM /CE and /CAS0 for ROM /OE.
http://segaxtreme.net/community/topic/1 ... -analysis/
There are a couple of things I'm curious about:
- How to detect a read from the /TIME area. Since it is only pulsed for reads and writes, I suppose checking for /LWR and /UWR inactive could be one way. But I wonder if one of the other read strobes like /CAS0 is valid in that range.
- Which signals on the cartridge connector change when /CART is pulled high, putting the system in Sega CD (floppy disk drive!) mode. In the linked thread patroclus02 answered some of this.
- Which signals become SMS signals in Mark-III mode. I gave up tracing a Power Base Converter, but I'm sure it would be easy to tell from a third party adapter (which may not hook up all the signals) or a Phantasy Star MD cart.
- Which signals are affected by enabling DRAM refresh mode in $A11000.
- In general what the purpose of the uncommon strobes are; nearly all games use /CE0 for ROM /CE and /CAS0 for ROM /OE.