Amiga and esp-link

[jbilander]

I altered the SDBox-v2 case and made a 3D-print to check on mechanical adaptation...






It's a bit tight accessing the MicroSD-card slot...


I think I will modify the case lid somewhat and open up for the micro-usb jack and the two buttons on the devkit board...and solder the Devkit-board a few millimetre higher up so it gives more room for accessing the MicroSD-card.

A bit more elevated, something like this...

[hooverphonique]

Looks like there's plenty of SD access room if you remove the USB cable first, but the photos could be misleading..

[jbilander]

Originally Posted by hooverphonique

Looks like there's plenty of SD access room if you remove the USB cable first, but the photos could be misleading..

yep, you are right there is plenty of room then, but I was thinking if you wanna hot-swap to another card, not that it's needed for the file transfer application (FTP-server etc) I'm tinkering with at the moment, but if someone wants to port the SDBox-functionality it can be good. The card-detect line is routed/prepared to one of the inputs (with a pull-up resistor for this) which gets grounded when a card is inserted in the slot.

[jbilander]

New design, this gives plenty of room for fiddling with card swaps and also access the two buttons on the Devkit-board.





Still waiting on components in order to solder it down like that so I can try this device.

[jbilander]

Did some more hacking on this project...

I can now Telnet into the ESP32 from the PC and run ls/dir and cd commands, and also connect from the Amiga via a serial terminal to do the same.

https://drive.google.com/file/d/1FhC...ew?usp=sharing

And from before you can transfer files to/from the ESP-device via FTP using your PC for example. The idea is once you have put files on the MicroSD-card via ftp you can control everything from the Miggy to transfer Amiga<->ESP32 over the parallel-link. A Parallel-link protocol remains to be implemented.

[jbilander]

Some update regarding this hobby-project...

I got a second ESP32 ($7 from Ali) that I have now soldered down to the carrier board.



Still waiting on some LEDs, they are on the slow boat from China, so I nicked a couple from the TTL-board because they are difficult to solder (D4,D5) once the Devkit-board is in place:



I used some plastic strip as tmp-standoffs to get the correct height on the Devkit-board while soldering.






Here a short vid when I move a file from the PC to the ESP32 via FTP and listing it on the Amiga.

https://drive.google.com/file/d/1_aY...ew?usp=sharing

I don't know yet if the parallel-port communication will work. Will try that next when I have time.

[eXeler0]

Video wont play for some reason, but, wow, nice. I could use a couple of those ;-)

[jbilander]

Originally Posted by eXeler0

Video wont play for some reason, but, wow, nice. I could use a couple of those ;-)

Oh, I see, for me it works in chrome and safari but not firefox for some unknown reason, anyway the other day I started hacking on the Amiga client to test to send and receive some bytes through the parallel port using the parallel.device. It is just to verify that the communication works.
I'm using bebbo's excellent amiga-gcc toolchain, many thanks to bebbo for making it.



For those interested the code is here:
https://github.com/jbilander/amiga-pario

With this I think I can verify POC (Proof Of Concept). It works on 1.3 too as you can see from the screenshot . Now I will just have to write some code on the ESP32 side and I should be ready to test if the hardware works as intended to ping-pong data across.

[jbilander]

yay, hardware seems to be working

Here I just relay the incoming bytes from the parallelport to the ESP32 Serial1-port where the Miggy also is connected to from its serial port, just to verify data is correctly received:

https://drive.google.com/file/d/11OK...ew?usp=sharing

[Amiga1992]

This looks really good!
Can this be used to connect an esp32 to an Amiga or other computers and use them as wifi modems too? Or would it just work with the esp-link software?

Oh wait, you're connecting this to the parallel port, not serial?

[jbilander]

Originally Posted by Amiga1992

This looks really good!
Can this be used to connect an esp32 to an Amiga or other computers and use them as wifi modems too? Or would it just work with the esp-link software?

Oh wait, you're connecting this to the parallel port, not serial?

Hi, thanks, yes you can connect both to the parallel-port and to the two UARTs. UART1 and UART2 are easily accessible with pins on the back, you will need a RS232/LVTTL-converter. Then it is a matter of writing/developing and flashing firmware to the ESP32. I think for example the plipbox and/or the sdbox firmware could be ported. Perhaps a plipbox with wireless internet could be possible. However my project is much simpler than that and won't require a TCP/IP-stack on the Amiga, my goal is to just have an easy way of copying files to/from the Amiga over the parallel-link to/from the ESP32 which in turn has a FTP-server running which I can access from my PC over wifi. It will function as an intermediate filehub or backup-store if you will where the files are stored to the MicroSD-card on the device. exFAT-formatted cards can be used too so there can be a lot of data stored if a 1 TB card is used, heh .

[jbilander]

I have made the hardware repository public now in case someone else wants to tinker with this too, hardware seems to work fine but no guarantees...you can find the pin-mapping I've used in the schematic pdf in the root of the repo.

https://github.com/jbilander/Parallel_to_ESP32

The stl-files and the source for the 3D-printable case is in the 3D folder.

Remember it is released under a copy-left license, if you build/modify from this source you are obligated to share your work with the rest of the Amiga Community, so that we can have great things!

Happy Hacking!

[lesta_smsc]

Nice project! are you selling these premade at all?

Is there any scope to use this for gaming purposes wirelessly between 2 Amigas without using null-modem cable? For example, rather than this being a parallel port to ESP32, to have Serial to ESP32!? You can imagine a market for that for gaming conventions to have Amigas networked wirelessly playing Stunt Car Racer, Lotus etc...

[jbilander]

Hi, thanks, no it's a DIY hobby project. I have a few spare boards and connectors but no spare CB3T-chips or Devkit-boards.
Regarding wirelessly playing Stunt Car Racer. I think it would be fairly easy to connect two ESP32 together and tunnel the serial data through back and forth. You can look for example at ESP-MQTT or ESP-NOW here https://randomnerdtutorials.com/esp-...ication-esp32/.
Wireless would introduce some lag but maybe it isn't noticable in game play.

On the Parallel_to_ESP32 board I have made UART1 (TX1,RX1) and UART2 (TX2,RX2) available with headers in the rear as you can see from the pics. I use it mainly for "Debugging", invoking commands and verify output during development but it would be possible to implement for example a Kermit-Server running on UART2 where other vintage computers could be connected for file transfers, a C64 (with RS232/LVTTL interface) for example, or it could be used for reading/writing Stunt Car Racer serial data and relaying it out on wifi. I don't know if SCR only uses TX,RX signals or if more pins are involved in the serial handshake CTS,RTS? Anyway it should be possible to do with not too much effort in development.

[jbilander]

The other day I did some tests on how quick the ESP32 can respond to interrupts...my thinking is that it should be quick enough to keep up with the Amiga when it's hammering the metal at full (2E) speed with a fast accelerator. I first tried a normal interrupt (level 3 and below) and it turns out the ESP is pretty slow taking some 2us (microseconds) or so to react, so I started to investigate further, can it be quicker?...and I found this blog post that describes howto set up an external level 5 interrupt:

https://haydendekker.medium.com/esp3...z-56f8dbb6a61c

I tried this and now it's fast You have to clear the interrupt from assembly code and then I toggle the BUSY-line by clear/set the register directly after, just to see how quick the "acknowledge" can be, and like the blog post I see some 330-360 ns period from external interrupt to setting the output value. Looks promising to use this when reading the data and stuffing into a buffer perhaps. However from an external level 5 interrupts it's not possible to call an ISR (Interrupt Service Routine) in C so it has to be done in xtensa-assembly in that case.

Here is a vid on one of the tests, I ran it when at the same time stressing it with a FTP-transfer and it didn't miss a beat
https://drive.google.com/file/d/1T3j...ew?usp=sharing

Pretty cool.

The assembly for the level 5 is here:
https://github.com/jbilander/ESP32-P...src/highint5.S

and here is howto setup the interrupt in C:
https://github.com/jbilander/ESP32-P...Server.cpp#L50

[jbilander]

wow, I didn't realise that Olsen has written a tFTP client for the Amiga and that it doesn't need a TCP/IP-stack.

http://aminet.net/package/comm/tcp/sana2-tftpclient

https://github.com/obarthel/amiga-sana-ii-tftpclient

This might be the missing piece for my Parallel_to_ESP32 to be able to send files back and forth between the Amiga and the ESP32 unit. I wonder if his tFTP-implementation runs ontop of plip.device?

http://aminet.net/package/comm/net/magPLIP38.1