Author
| Yamaha CX5M Upgrades/PCB
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ALH
msx user
Posts: 57 |  Posted: January 20 2004, 23:34 |
Right .. ive finaly gotten around to lookin at my MSX
and im woundering why it sems to think ive only got 21558 or around abouts of ram
I need the sort of blue prints to this motherboard
im guessing the D416C-3 are the main memory chips
but i dont have a clue as i know some of these chips the 74 Logic gates and the Z80
but the rest i dont know
as i said i would like a blue print of the board and th chips
also any upgrades if you know any
do note i only know english .. so any thing to read has to be translated or in english
a lot of you fans are dutch and other non speaking english
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GuyveR800
msx guru
Posts: 3048 | Posted: January 21 2004, 09:07 |
In MSX the memory that can be used in BASIC is very limited. Don't worry, your MSX has 64K RAM, even though BASIC only mentions '21558 bytes free'.
This is because the BASIC and BIOS ROM occupy the lowest 32K of the Z80 addressing range, the upper 32K is RAM. In that RAM resides the system area, with all the variables and reserved locations that the BASIC and BIOS needs, and ofcourse the stack.
21558 sounds a bit low to me, IIRC it should be more like ~27000.
Your MSX is fine, trust me.  |
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Argon
msx professional
Posts: 842 | Posted: January 21 2004, 09:45 |
Quote:
| In MSX the memory that can be used in BASIC is very limited. Don't worry, your MSX has 64K RAM, even though BASIC only mentions '21558 bytes free'.
This is because the BASIC and BIOS ROM occupy the lowest 32K of the Z80 addressing range, the upper 32K is RAM. In that RAM resides the system area, with all the variables and reserved locations that the BASIC and BIOS needs, and ofcourse the stack.
21558 sounds a bit low to me, IIRC it should be more like ~27000.
Your MSX is fine, trust me.
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Yes, even a turboR GT with 512K RAM has so little in basic  |
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ALH
msx user
Posts: 57 | Posted: January 21 2004, 16:10 |
has any one tried to over clock the Z80 CPU
with moden PC fans could chil it down before it knows about it
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GuyveR800
msx guru
Posts: 3048 | Posted: January 21 2004, 16:13 |
Yes..
The Z80B used in the early 7.16MHz upgrades is rated at 6MHz, so it was overclocked to 7.16.
The R800 in the turboR can be overclocked to 10MHz (from 7.16), but at that speed the VDP will start showing glitches. Anything faster than 8MHz doesn't work.
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Jazzy
msx addict
Posts: 411 | Posted: January 21 2004, 16:24 |
Quote:
| Yes..
The Z80B used in the early 7.16MHz upgrades is rated at 6MHz, so it was overclocked to 7.16.
The R800 in the turboR can be overclocked to 10MHz (from 7.16), but at that speed the VDP will start showing glitches. Anything faster than 8MHz doesn't work.
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I guess you are mistaking, the R800 runs at 28.64 MHz and can be overcocked to 40 MHz. |
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GuyveR800
msx guru
Posts: 3048 | Posted: January 21 2004, 16:25 |
That's the crystal used. The actual R800 clocksignal is divided by 4.
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ALH
msx user
Posts: 57 | Posted: January 23 2004, 16:43 |
Didnt i see a Z80 CPU in a GameBoy being Overclocked to 100MHz !!
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snout
msx legend
Posts: 4992 | Posted: January 23 2004, 16:53 |
that was a hoax  Especially read the second page of that website, where they are 'burning in' a Z80 |
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