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PSX Thingy
Posted: September 13th, 2016, 2:59 pm
by CyrusDevX
Can the psx use a pin per pin matching parallel flash ic on the address and data lines on the pio port, with ce rd wr too? Also meaning not using a gal logic chip like in the xploder carts. Does the psx auto map the new chip and would be able to boot unirom forexample?
http://i.imgur.com/wb8UoAy.jpg
Sorta like a xploder concept. with a host pc app.
512KB external bios
512KB external pio rom
ATmega1284p MCU
2x MCP2221
PIC16F629
74HC245 Latch
Re: Question
Posted: September 13th, 2016, 3:08 pm
by Administrator
Yes, if you flash the correct bootcode and the right header, the PSX will boot from ROM over the parallel port BEFORE anything else.
Re: Question
Posted: September 14th, 2016, 1:42 am
by CyrusDevX
ty
Re: PSX Thingy
Posted: September 22nd, 2016, 9:25 am
by sickle
I get the software side of things, but I've never really looked into the hardware.
Does it need much glue logic or anything? Or does each pin on the p.port just kinda map to the EEPROM?
Like the XPlorer FX has 512k, 384k of which is actually wired to the PSX, and PSIO has 32k or something can you get away with minimal wiring for something really simple?
Re: PSX Thingy
Posted: September 22nd, 2016, 9:39 am
by CyrusDevX
I'll start wiring the ROM on the parallel port here soon, been busy with random stuff but I managed to build (another) serial cable for net yaroze support specifically.
In Addition the latch on the atmega is just to work as buffer / access control on the 8bit data bus. latching off the mcu's control.
