Pi Pico auf einer ISA-Karte (Pi Pico on an ISA Board) - PicoMEM - kennt das jemand?

FreddyV · Jul 5th 2023

Quote from tofro

Quote from lgp30

Aha, wieder ein Projekt "ich bastele mal was, weiß aber nicht, wozu"
Wenn ich das lese, erschließt sich mir der Sinn dieses Teils überhaupt nicht. Man kann definitiv keine altbekannten I/O-Karten damit emulieren, sonder ist darauf angewiesen, auf PC-Seite passende Treiber zu schreiben.
On this board, I did put:
- Connection to the full Memory and I/O BUS
- One IRQ
- No DMA
- MicroSD Connector
- 8Mb of PSRAM

Vor allem die Einschränkungen bezüglich IRQ und DMA sind ein k.o.-Kriterium für alles außer Speicher.
Echte Laufwerke kann es nicht emulieren. Es ist darauf angewiesen, einen eigenen BIOS-Code mitzuliefern, um das ganze dann per Polling (uff, das auf einem XT) in den Hauptspeicher zu überführen. Also nix mit XT-IDE, Floppy und Co.

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Eigentlich verstehe ich deine Kritik nicht ganz. Ein IRQ reicht eigentlich, um von der Karte aus dem PC ein "kuck mal" zu signalisieren - Polling ist dann nicht notwendig. Der Pico kann ein Register zur verfügung stellen, das dem PC nach einem IRQ signalisiert, was genau zu tun ist.

Genauso sehe ich keinen Grund für einen DMA-Kanal zur Karte: Wenn der gesamte Memory- und I/O- Adressraum für den Pico zugänglich ist, sehe ich keinen Grund, "langsame" PC-DMA zu verwenden, wenn der Pico sich kurz den Bus greift und dann wesentlich schneller schreiben und lesen kann.

Das ganze "widerspricht" ein bißchen dem klassischen Konzept einer ISA-Erweiterungskarte, das stimmt. Aber wenn man schon einen modernen Controller auf der Karte hat, sollte man ihn auch verwenden. Treiber auf der PC-seite sind dann zwar vollständig anders als im "klassischen" Ansatz, aber u.U. auch wesentlich einfacher. Die SOftware auf der Pico-Seite wird halt komplexer.

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Hi,

I see you agree with me

There is no need to add 4 IRQ when one is enaugh.

The Board will do what almost no other board is doing, but I don't think there is any rule saying : An ISA Board can't do this.

ISA Board with Dual port RAM exist, ISA Board with co processor exist and so on...

My Board is there to simplify the life of retro enthousiast.

When I see lot of person asking for Help to install a simple XTIDE.... I think I am doing the right thing.

Peter z80.eu · Jul 7th 2023

Quote from FreddyV

On this board, I did put:

- Connection to the full Memory and I/O BUS

- One IRQ

- No DMA

- MicroSD Connector

- 8Mb of PSRAM

Quote

Also nix mit XT-IDE, Floppy und Co. (translated: So no plans for XT-IDE alike, Floppy and similar...)

Hi,

I know what I am doing.

When available, everybody will be able to do what they want with it, I don't force anybody.

With an IRQ and a ROM Emulation/Its own ROM the board can use any Hardware and Software IRQ.

So, there is no limitation there.

The abscence of DMA signal does not mean it can't do DMA...

The board can capture what is sent to the DMA controller and emulate a DMA cycle through the IRQ and the BIOS.

See what I wrote above for the Floppy emulation and XTIDE...

My board do exactly like an XTIDE, but emulate the BIOS itself

The XTIDE does not emulate an MFM because it does not have to.

Why the PicoMEM should emulate an IDE, that did not exist on XT back in the day ? It is only a waste of time and risk of bug added.

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Hi FreddyV , nice to see your contributions also here.

For me and I guess, not only for me, the question is what can I do with this card. Yes, there are many ideas, many possibilities for an implementation, but not all here will be able to write their driver software for themselves/for all other.

So, like always, it depends that someone will implement also driver software for it, not only EMS driver (which will be welcome, too) but also for an emulation of other storage devices. If the board does not emulate a XT-IDE controller, that will be fine, if any kind of an other mass storage will be usable, e.g. similar to the SD-card drivers for the Atari ST SD card devices for example. Only a fraction of existing original software are really accessing hardware in a "low level" way, most of the existing software rely on a BIOS or on software drivers. So I will be happy about other but already implemented purposes for this promising piece of hardware and waiting for your annoucements...

FreddyV · Sep 13th 2023

Hi,

Sorry but I don't really understand what you mean.

For floppy and disk, there is no need for a driver the board emulate ROM, has its bios that implement the bios standard functions.

For the EMS, it is compatible with LTEMM, so use the same driver.

For mouse, i will provide a modified CTMouse.

If I add network it will be ne2000 compatible.

For usb joystick, hardware compatibility.

Usb keyboard, its bios can directly add the Keys in the buffer.

And so on.....

For not existing functions, it will be to simplify the life of people developping software on old PC.

It is not like the opl3lpt needing to mofify all the games.

Regarding compatibility, it will not support floppy copy protected games, but all are cracker

Application accessing disk and floppy directly are disk copier, didk utility that nobody need to use with a board like this.

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