Raspberry Pi Pico as Akiko on Clockport

[pandy71]

Originally Posted by Gorf

I don't understand the problem here: the wiring would be almost identical to the Atari ST solution. For joystick and mouse it is even 1:1 identical.

For the A1000 keyboard even the same phone-jack ist used as in this projekt.
For A2/3/4000 you only need a different connector, but the same amount of wires. Only the serial protocol differs.

Then perhaps i don't get correctly your idea - if your goal is to emulate some functionality but use existing Amiga IC's (so you simulate at normal Amiga ports signals of external devices) or you use Amiga bus to replace some existing functionality and add new one on top?

btw - 74ACT299 looks like good candidate for expanding available I/O's in RP2040 (bit slow as fmax is around 90MHz, 74FCT299 could be better but seem it is obsolete - perhaps some faster shifters are still produced) - this will simplify also level translation as serial interface has less pin's to translate.

[Gorf]

Originally Posted by pandy71

Then perhaps i don't get correctly your idea - if your goal is to emulate some functionality but use existing Amiga IC's (so you simulate at normal Amiga ports signals of external devices) or you use Amiga bus to replace some existing functionality and add new one on top?

look at the link I provided
https://github.com/fieldofcows/atari-st-rpikb

Just an Interface Adapter: USB-Mouse, USB-keyboard, USB-Joystick/Gamepad for classic amigas - connect all kinds of USB HIDs zu the Amiga with just one Pico.

Good point to start IMHO.

[pandy71]

Originally Posted by Gorf

look at the link I provided
https://github.com/fieldofcows/atari-st-rpikb

Just an Interface Adapter: USB-Mouse, USB-keyboard, USB-Joystick/Gamepad for classic amigas - connect all kinds of USB HIDs zu the Amiga with just one Pico.

Good point to start IMHO.

Checked link after your earlier post - IMHO this doesn't require RP2040 and any USB host capable uC can do this - PIO gives us opportunity to interface things directly to Amiga bus that's why RP2040 can be serious advantage over STM32 or similar uC's.

But if this suit your needs then indeed this is very neat project.

[Gorf]

Originally Posted by pandy71

Checked link after your earlier post - IMHO this doesn't require RP2040 and any USB host capable uC can do this - PIO gives us opportunity to interface things directly to Amiga bus that's why RP2040 can be serious advantage over STM32 or similar uC's.

But if this suit your needs then indeed this is very neat project.

It is a nice way to start playing with this little board and get familiar with it.
Und it might be fun.

Everything else we talked here sounds more like serious and hard work with a good chance of getting frustrated along the way...

(And I would not have halve the equipment and tool and spare amiga boards and chips to even start with it something like a custom chip replacement ... let alone the time)

[pandy71]

Originally Posted by Gorf

It is a nice way to start playing with this little board and get familiar with it.
Und it might be fun.

Everything else we talked here sounds more like serious and hard work with a good chance of getting frustrated along the way...

(And I would not have halve the equipment and tool and spare amiga boards and chips to even start with it something like a custom chip replacement ... let alone the time)

I agree with you so no need to explain - just pointed that any USB host capable uC can do this and current USB stack in RP2040 seem to have some problems so perhaps using something more mature like for example STM32 could be better.

Also i don't expect few week easy work to do such thing on RP2040 - rather painful and time consuming exercise.

And equipment luckily for Amiga is not so expensive - logic analyzer (Saleae or its clone are quite inexpensive and 8 channels should be more than OK)
Side to this some scope and i think no more than this (beside of course time).

[Bruce Abbott]

Originally Posted by Gorf

After some reading of the specs of the new "Raspberry Pi Pico" microcontroller I came to the conclusion that this 4€ board might be a good fit for the Amiga Clockport (with some level-shifters of course)

So not really a good fit.

I would be nervous about designing any project using this board because there is only a single source and their reputation for availability is not good.

[Gorf]

Originally Posted by Bruce Abbott

So not really a good fit.

I would be nervous about designing any project using this board because there is only a single source and their reputation for availability is not good.

Any better suggestions for a RP2040 board?

[pandy71]

Originally Posted by Bruce Abbott

So not really a good fit.

I would be nervous about designing any project using this board because there is only a single source and their reputation for availability is not good.

Initially original Raspberry Pi Pico board has best price/capability ratio - target would be dedicated board(s) for Amiga that can be easily inserted to IC's sockets.

And there is many boards with RP2040

https://en.wikipedia.org/wiki/RP2040#Boards

uC are usually single source and RP2040 is not exception - so rather safe choice - alternatively only TI produce uC with embedded something like PIO (PRUSS - Programmable Real-time Unit Subsystem) btw i have impression that guys behind RP2040 was heavily inspired by TI - instead designing specialized HW they just designed universal, real time I/O uC embedded side to general uC.

[stevelord]

Originally Posted by Gorf

Any better suggestions for a RP2040 board?

Surely that depends entirely on the application. Bruce is right, it's all fun and games until you can't get a Pico. Choose the best chip for the product, not the other way around.

[pandy71]

Originally Posted by Gorf

The mentioned use case a line-doubler made me think.
It should be possible to do more with this ... specifically all things that process video-output line by line without the need of storing a field or frame.

The DCTV, HAM-E and Graffiti work this way ...

Would a "all in one" solution be possible?

Forgot about one thing that was used out of Amiga world but it is very tempting idea to try it also in Amiga - Edsun CEG RAMDAC (later Edsun was acquired by Analog Devices and technology was used to implement in ADV7141, ADV7146 and ADV7148 .
idea is described here http://archive.gamedev.net/archive/r...rticle371.html and in datasheet for ADV714x.

[Gorf]

Originally Posted by stevelord

Surely that depends entirely on the application. Bruce is right, it's all fun and games until you can't get a Pico. Choose the best chip for the product, not the other way around.

This is not the purpose of this thread ;-)
I am not trying to solve a certain problem and looking for the best chip to do the job, but looking for an application for exactly the RP2040.
It does not need to be a Pico-board but could be one of the clones as well, but the question is, what can we do wit the RP2040.

[stevelord]

Originally Posted by Gorf

This is not the purpose of this thread ;-)
I am not trying to solve a certain problem and looking for the best chip to do the job, but looking for an application for exactly the RP2040.
It does not need to be a Pico-board but could be one of the clones as well, but the question is, what can we do wit the RP2040.

What can we do wit the RP2040? Why not a drunken sailor, early in the morning?


It's a 3.3v GPIO single vendor Cortex M0+ board. It's not great for anything internal without level shifters and buffers, which complicates some of the features you might want to use for internal applications.


It's probably better suited to external applications taking advantage of the MP2040's features (SPI etc). It's in competition with an Arduino Nano, which may be less powerful but doesn't need level shifting.


If you insist on hammering a square peg regardless of hole shape start with getting clean power and bidirectional comms signals and work back to the controller.

[pandy71]

Originally Posted by stevelord

What can we do wit the RP2040? Why not a drunken sailor, early in the morning?


It's a 3.3v GPIO single vendor Cortex M0+ board. It's not great for anything internal without level shifters and buffers, which complicates some of the features you might want to use for internal applications.


It's probably better suited to external applications taking advantage of the MP2040's features (SPI etc). It's in competition with an Arduino Nano, which may be less powerful but doesn't need level shifting.


If you insist on hammering a square peg regardless of hole shape start with getting clean power and bidirectional comms signals and work back to the controller.

Obviously you don't understand difference between regular ARM core uC and RP2040 - only TI offer something like PIO in RP2040 (TI is more flexible and complex) - RP2040 offer real time capability in software something like XMOS - with software driven flexible HW you can deal with real time signal over 100MHz i.e. RP2040 act more like very complex CPLD or FPGA with added 2 ARM cores...
As Amiga is relatively slow then RP2040 in theory can deal with Amiga HW directly with software. Comparable HW solution are BeagleBone board but they cost between 39 and 99$ however they offer way more (like 3D GPU, HDMI, 512MB RAM etc) - still 4(1)$ RP2040 offer possibility to emulate Amiga IC's...

[Promilus]

@pandy - I wouldn't go that far. I mean:

RP2040 act more like very complex CPLD or FPGA with added 2 ARM cores

That just isn't true. All this chip has over regular Cortex M is PIO itself. It's amiga-style fixed function program controlled unit. So like blitter and copper it has very limited instruction set but do things fast. And now... with CPLD you can easily make logic which handles all 23/24 address lines necessary for Amiga and 16/32 data lines and host of additional signals either 68k generated like VPA, AS, R/W etc. or chipset generated like IRQ which also has to be synced on either level, falling or rising edge and response should be in specific timeframe. You can't do that on Cortex-M microcontrollers, even such as RPI2040 with PIO. PIO is great to handle things many chips has to bitbang (like addressable RGB led protocols) or specific fast actions across few pins. It isn't well suited to handle parallel bus spanning over few dozens of signals. Also - it still would need decoding - what bus signal means and how to handle it, where inside ARM memory data should go etc. etc. With TI Sitara line you have GPMC which is capable of handling 16bit A500/600/2000 bus without much of a problem. And it can map all amiga space to ARM space so all you need is apply fixed offset to communicate with Amiga HW. Therefore it makes perfect sense to use such SoC if indeed parallel memory interface is required (and that's kind of architecture Amiga chipset has). RPi2040 just isn't suited for this. It's way better than STM32, yes, but still has a long way to go.

All engineers takes a problem, analyze it, search for best tools for solving that problem and then apply solution. This thread is for something different. Author got himself a tool and now seeks a problem in Amiga hw which can be solved with it. And while there are some which might it doesn't make it perfect fit. It doesn't even make it reasonable. And FYI there's already pretty old solution from Cypress (PSoC4,5,6) which really has programmable IO matrix (CPLD like) and it didn't find its way into amiga before. Why the hell you think RPi should? All it has over solutions already on the market is community. You say about price... ppl spent money on hundred dolar chips (fpga like Cyclone V) and even more expensive boards to get performance way below level of 10$ ARM SoC (like H5 from Allwinner). Price alone doesn't make RPi "right" solution. And neither does PIO. And unless you show me how RP2040 handles emulation of e.g. Fat Agnus inside real amiga you shouldn't make such statements.

[stevelord]

Originally Posted by pandy71

Obviously you don't understand difference between regular ARM core uC and RP2040 - only TI offer something like PIO in RP2040 (TI is more flexible and complex)

I've made my point, no need for me to rehash it. You won't change my mind and I won't change yours. Looking forward to seeing what you build with it. Best of luck.

[pandy71]

Originally Posted by stevelord

I've made my point, no need for me to rehash it. You won't change my mind and I won't change yours. Looking forward to seeing what you build with it. Best of luck.

Well, it is not about changing your mind - it is about having discussion based on facts. So whenever somebody placing equal sign between RP2040 and other uC with ARM core (not equipped with something like PIO) then some facts need to be refreshed so discussion can be based on them. That's all.

Sadly to say my main issue for today are insane prices of the construction materials in my country - some of them rose over few hundred % and simply i have no time for RP2040 for Amiga.
So i shared some ideas hoping that perhaps somebody is less busy and able to have fun with RP2040 in Amiga.
But anyway thanks for all wishes and i can say - the same for you.

[pandy71]

Originally Posted by Promilus

@pandy - I wouldn't go that far. I mean:

That just isn't true. All this chip has over regular Cortex M is PIO itself. It's amiga-style fixed function program controlled unit. So like blitter and copper it has very limited instruction set but do things fast. And now... with CPLD you can easily make logic which handles all 23/24 address lines necessary for Amiga and 16/32 data lines and host of additional signals either 68k generated like VPA, AS, R/W etc. or chipset generated like IRQ which also has to be synced on either level, falling or rising edge and response should be in specific timeframe. You can't do that on Cortex-M microcontrollers, even such as RPI2040 with PIO. PIO is great to handle things many chips has to bitbang (like addressable RGB led protocols) or specific fast actions across few pins. It isn't well suited to handle parallel bus spanning over few dozens of signals. Also - it still would need decoding - what bus signal means and how to handle it, where inside ARM memory data should go etc. etc. With TI Sitara line you have GPMC which is capable of handling 16bit A500/600/2000 bus without much of a problem. And it can map all amiga space to ARM space so all you need is apply fixed offset to communicate with Amiga HW. Therefore it makes perfect sense to use such SoC if indeed parallel memory interface is required (and that's kind of architecture Amiga chipset has). RPi2040 just isn't suited for this. It's way better than STM32, yes, but still has a long way to go.

Depends - PIO is capable to shift IN or shift OUT up to 32 bits over single pin automatically (embedded programmable primitive SERDES) as such using shift register you can connect parallel bus to RP2040 and considering speed of the Amiga bus (280ns cycle) you can do a lot as RP2040 basic cycle is 7.5ns - and there is nothing wrong to sample Amiga clock and synchronize RP2040 to this clock so everything will be correct from timing perspective. Additionally shift register will do voltage translation (not sure about such hype around voltage translation - this is normal, easy to solve design task).
If you need lower latency then you can use multiple shift register (like 4x8bit to deal with 32 bits), you can use multiplexers (even analog one so bidirectional).

Instead single TI AM3358/AM5729 you can use 1$ RP2040 for single task (such as CIA emulation).
I agree about AM3358/AM5729 capabilities but they cost more so RP2040 is IMHO nice alternative to CPLD/FPGA at least on some functions. 133MHz is speed higher than offered by most of 5V CPLD's.
That's why i used this comparison.

Originally Posted by Promilus

All engineers takes a problem, analyze it, search for best tools for solving that problem and then apply solution. This thread is for something different. Author got himself a tool and now seeks a problem in Amiga hw which can be solved with it. And while there are some which might it doesn't make it perfect fit. It doesn't even make it reasonable. And FYI there's already pretty old solution from Cypress (PSoC4,5,6) which really has programmable IO matrix (CPLD like) and it didn't find its way into amiga before. Why the hell you think RPi should? All it has over solutions already on the market is community. You say about price... ppl spent money on hundred dolar chips (fpga like Cyclone V) and even more expensive boards to get performance way below level of 10$ ARM SoC (like H5 from Allwinner). Price alone doesn't make RPi "right" solution. And neither does PIO. And unless you show me how RP2040 handles emulation of e.g. Fat Agnus inside real amiga you shouldn't make such statements.

Fair except one thing - you talking about mass production, factory approach where it work like this - for hobbyist like most of us cleverly used cheap HW may be more attractive.
And to be honest i don't need to prove anything to you or anyone else - if RP2040 is capable to produce valid DVI video using PIO and software then it may be also capable to do things which are less time critical.
And if thread is read carefully then i'm quite skeptical about Agnus emulation due first, some internal logic is still not sufficiently documented secondly, relatively big number of I/O required to deal with RAM and CPU+RGA. Hope it is clear.
Beagle bone better than RP2040 - yes, no doubts on this but also it is more expensive especially if you think on single IC's emulation.
Agnus in RP2040 perhaps yes, perhaps no, no one tries for sure so why assume upfront that this is impossible.

Btw forgot to add - Cypress was expensive and as such not highly popular... And some wiling to spent hundreds of $ some others not... luckily there is still some shopping freedom - hope RP2040 based solutions will be affordable for anyone.
My internal RP2040 Amiga priorities are CIA's, Paula and Denise.