Yarek's 4MB ram expansion

[arnoldemu]

The download link on Yarek's page for the schematics for the 4MB ram expansion do not work. I get a 0 byte file.
Does anyone have it or can they upload it to the wiki please?

[TotO]

May be better to ask it to him?
By the way, hacking his 6128 mainboard is not a good way to expend the 6128 RAM today.

[Bryce]

I've only ever seen one of Yareks 4MB expansions and it was an external device, no hacking required.

Bryce.

[gerald]

The download link on Yarek's page for the schematics for the 4MB ram expansion do not work. I get a 0 byte file.
Does anyone have it or can they upload it to the wiki please?

I've seen that asked for at least 4 time on the wiki forum, with always the same result. No files and no answer from Yarek 

[TotO]

OK... 

[KaosOverride]

Isn't the 4 MB external expansion  just a normal expansion with 8x512Kb blocks and an extra 8bit buffer at some I/O port to select the 512kb block?

And the internal, has sense just for hacking the A14-A15 from 6128 PAL and have the extra mapping modes...

[Bryce]

Yes, that about sums it up as a far as I can remember.

Bryce.

[arnoldemu]

Yarek's website claims A15-A11 are 01111.

But if it's using the PAL and only using /CAS1 then in fact this is true:

A15-A11 0xxxx.

PAL decodes bit A15 only for the i/o address.

I was hoping to get the schematic to confirm the I/O decoding.

[TotO]

Isn't the 4 MB external expansion  just a normal expansion with 8x512Kb blocks and an extra 8bit buffer at some I/O port to select the 512kb block?

And the internal, has sense just for hacking the A14-A15 from 6128 PAL and have the extra mapping modes...

I doubt that expansion allow to support extra PAL modes over the 8x512kB[nb]Sometime wrote KB, but not Kb = kilobit[/nb] RAM blocks.

[gerald]

I doubt that expansion allow to support extra PAL modes over the 8x512kB[nb]Sometime wrote KB, but not Kb = kilobit[/nb] RAM blocks.

Why not ? The 'extra' mode are managed by the PAL. The only thing you need to extend the standard 512K is more bank select bits and associated decoding, (and refresh for the additional DRAM ROW addresses).

[gerald]

Yarek's website claims A15-A11 are 01111.

But if it's using the PAL and only using /CAS1 then in fact this is true:

A15-A11 0xxxx.

PAL decodes bit A15 only for the i/o address.

I was hoping to get the schematic to confirm the I/O decoding.

Anyone having one of these interface to test ?

[TotO]

Why not ? The 'extra' mode are managed by the PAL.

You are true, it is a 6128 expansion only... A bit of confusion with the 464/664 RAM expansion topic. 

[rpalmer]

gerald,

While the I/O address of the VGA is A15 low, the use of the A14 to A11 lines should not be low when A15 is low as these are also used to select the other devices.
So Yarek is correct in correct in stating the values for A14 to A11 must be '1'.

rpalmer

[gerald]

While the I/O address of the VGA is A15 low, the use of the A14 to A11 lines should not be low when A15 is low as these are also used to select the other devices.
So Yarek is correct in correct in stating the values for A14 to A11 must be '1'.

I know that, but I think arnoldemu would like to be sure that the ram extension really react only to "0111" and not to "0xxx" to emulate it properly.
The PAL in 6128 only cares about A15.

[arnoldemu]

I know that, but I think arnoldemu would like to be sure that the ram extension really react only to "0111" and not to "0xxx" to emulate it properly.
The PAL in 6128 only cares about A15.

Correct. I want to emulate this ram expansion accurately.

[TFM]

Anyone having one of these interface to test ?

I got the internal 4 MB version of it. RAM replaced on PCB of the 6128. It also has 2.5 MB FlashROM. All works fine and reliable. Looks like a regular 6128 from the outside. If you have questions maybe I can help, but it's not much to it. Just access 8x 512 KB using 8 ports: &7Fxx, &7Exx, ... &78xx.


Sadly people are still crawling with 512 KB Expansions. 4 MB is just way more fun. 

[arnoldemu]

I got the internal 4 MB version of it. RAM replaced on PCB of the 6128. It also has 2.5 MB FlashROM. All works fine and reliable. Looks like a regular 6128 from the outside. If you have questions maybe I can help, but it's not much to it. Just access 8x 512 KB using 8 ports: &7Fxx, &7Exx, ... &78xx.


Sadly people are still crawling with 512 KB Expansions. 4 MB is just way more fun. 

If I make a test program would you run it on your 6128 with 4MB?

[TFM]

If I make a test program would you run it on your 6128 with 4MB?

Sure at X-Mas or next year in May. That's when I access the hardware. But you can just ask me for details. I know how it works.