MMC/SD drive newbie - need help | MSX Resource Center (Page 7/13)

By sharksym

Resident (38)

10-03-2009, 15:37

pitpan,

AT29C040A does not have sector erase command.
Erasing is done automatically, during chip internal flashing process.

By pitpan

Prophet (3155)

10-03-2009, 16:47

That's good to know, sharksym.

By Erikie

Champion (324)

10-03-2009, 19:33

OK, my program just flashed the first 256 bytes:
org 0100h

ld a,2
ld h,40h
call 0024h

ld a,2
ld h,80h
call 0024h

ld a,0
ld (5000h),a

ld a,01h
ld (0aff0h),a

di
ld a,0AAh
ld (09555h),a
ld a,055h
ld (06AAAh),a
ld a,0A0H
ld (09555h),a
nop
nop
nop
nop
ld de,04000h
ld hl,data
ld bc,100h
ldir
nop
nop
nop
nop
nop
nop
ei

ld a,00
ld (0aff0h),a

ld a,(0f343h)
ld h,80
call 0024

ld a,(0f342h)
ld h,40
call 0024
ret

data: DB 'THIS IS A TEST FOR LOADING DATA INTO THE ATMEL AT29C040A CHIP AND WE ARE GOING TO SEE IF THIS REALLY WORKS OR NOT ..............'
DB 'THIS IS A TEST FOR LOADING DATA INTO THE ATMEL AT29C040A CHIP AND WE ARE GOING TO SEE IF THIS REALLY WORKS OR NOT ..............'

By cax

Prophet (3740)

10-03-2009, 20:56

Cool ! I knew I miss some ex (sp),hl ; ex (sp),hl ; (like we do for VDP) somewhere. Will try that tomorrow.

By Erikie

Champion (324)

11-03-2009, 21:20

so finally finished my first prototype of v1.0 hardware with the help of a small cpld. It only uses 4 chips now
scc chip, at29c040a, 74ls30 (need this as I have not enough input pins on the cpld ) and epm7032s cpld. It works like a charm. Next step will be to use an scc mapper in the cpld to get rid of ripping scc roms. Then it is just 2 chips, flash rom and cpld.
Anyone interested in the prototype with the cpld?

By Huey

Prophet (2694)

11-03-2009, 21:46

Congrats Erikie!

Good luck on the SCC mapper implementation.

By cax

Prophet (3740)

11-03-2009, 22:21

And indeed it works. Just some waiting before LDIR - and bytes get flashed.
How stupid I am - I knew missing delay can be a problem, but didn't try it myself before.

By cax

Prophet (3740)

12-03-2009, 07:54

Erikie, good job ! Keep going. Having available cheap drive can motivate a lot of people to switch on their MSX again !

By pitpan

Prophet (3155)

12-03-2009, 10:13

That's great news! Looking forward to see a working prototype!

By Erikie

Champion (324)

13-03-2009, 17:02

I have a question regarding the slot select. Yesterday I tried my mmc 1.0 in slot 3.1 on my nms 8250 and it started XAK fine and I could play it fine. Allthough sharksym mentioned it does not work in expanded slot.
How does it work for a rom program, does it know in which slot it resides? As some programs just like xchgmmc.com is looking for the rom in specific slots. I need to modify these to work in expanded slot.
My plan is to have 2 sd drives instead of floppy drives in all my 8250/80s Diskrom is already removed as I do not need it. And with the MY connector in this machine it is pretty simple to make a device which can be placed in the drive bays which is connected by a flatcable to mainboard