#4799 - sgeos - Thu Apr 10, 2003 4:41 am
Is there anything preventing somebody from making a cart with more than 64k sram?
-Brendan
#4802 - tepples - Thu Apr 10, 2003 6:02 am
| sgeos wrote: |
| Is there anything preventing somebody from making a cart with more than 64k sram? |
Other than that Nintendo won't manufacture such a cart just yet?
The address space allotted to SRAM is only 64 KB, but the newest Visoly and F2A flash carts have 256 KB of SRAM in 64 KB banks. To learn how to bankswitch them, read the PogoShell source code.
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#4827 - sgeos - Fri Apr 11, 2003 4:12 am
I take this to mean 'No reason. Nobody has made one yet.' Does the AGB prevent the programmer from addressing over 64k? *Is* SRAM expensive?
-Brendan
#4828 - tepples - Fri Apr 11, 2003 5:58 am
| sgeos wrote: |
| 'No reason. Nobody has made one yet.' |
As I said, Visoly has made one yet.
| Quote: |
| Does the AGB prevent the programmer from addressing over 64k? |
The addressing window to SRAM is only 64 KB wide (0x0e000000-0x0e00ffff), but an addressing window never stopped NES developers, who used cartridge hardware called "mappers" to bankswitch memory.
GBA carts can use the slower kinds of SRAM because the hardware inserts several wait-states for every SRAM access, but I don't know how expensive SRAM is.
_________________
-- Where is he?
-- Who?
-- You know, the human.
-- I think he moved to Tilwick.
#4830 - ampz - Fri Apr 11, 2003 8:11 am
SRAM is one of the most expensive memory types, yes.