Idea: hybrid SX-1 + RPI 4

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By mcolom

Master (174)

mcolom's picture

25-10-2020, 13:46

These days the idea of building a hybrid MSX FPGA + Raspberry Pi 4 (RPI4) is wandering in my head.
I really like that the SX-1 board can be put inside a mini ITX PC case, and morever, there's plenty of room inside to add more things. Something I'd like to do is to do is to add a switch to choose to power up the SX-1 or the RPI4, and to share the micro-SD card between the SX-1 board and the RPI4. The RPI can communicate with the SD card via SPI, and all I'd need is to use one of the pins of the RPI as a control signal to connect the SD card (that by default will be connected to the SX-1), with an analog switch.
But looking at the board's picture in the manual I see that the pins of the SD card are made accesible, as well as the power on control (I don't know if you can power off with the same pin). It's really cool that the designer of the board did that Smile
I don't want to do anything complicated, just a little board with analog switchess (at least, for the SD card and the USB keyboard) and connectors to power up the SX-1 and the RPI4, an along switch to turn on the SX-1 or the RPI4, and little more. If I can connect to the Internet with the RPI, download files to the FAT-16 SD card, turn off the RPI, turn on the SX-1 and read the files in the card, I'll be more than happy!
If someone know more about the SX-1, please tell me. For example: which is exactly the power connector it uses? How to you power on/off (a button, or do you simple remove the power cord)? Can you do it with some control pin? There isn't much technical info around the SX-1 board :S

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By st1mpy

Hero (610)

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25-10-2020, 14:42

So basically you just want to put files downloaded onto the micro sd card in the SX-1?
You could achieve that by putting one of those wifi capable sd cards.
(since they tend to be a full sd card size, you would need a micro sd card to full sd converter)

By mcolom

Master (174)

mcolom's picture

25-10-2020, 15:12

I didn't know about those wifi SD-cards, thanks! I'm not sure if they can be formatted FAT-16 (it could be, since some of them are directly running Linux), and I don't to always remember that I shouldn't erase the part of the SD where its SO and applications are stored.
But anyway, my idea is to share the card with the RPI to, for example, run openMSX with the files of the card, and at the same time being able to use the files (say, load ROM files) in the SX-1 FPGA, and of course being able to insert real cartridges.
If I manage to get that, I think it'll be a cool hardware: you can use openMSX using the SD card as a hard disk, and at the same time you can use "real" (FPGA) hardware.
I know I could simply use an emulator in the PC, and move the card from the PC to the FPGA to copy files, but I find the idea of the hybrid system quite cool Cool

By NetNomad

Supporter (16)

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02-11-2020, 23:56

Have you seen this announced today?

https://www.raspberrypi.org/products/raspberry-pi-400/

It's an RPi 4 with an MSX-like form factor! This post was the first thing I thought of when I saw it, I wonder if you would be able to hook up an FPGA to this with the GPIO ports and be able to use the 400's keyboard in OCM mode. That would be pretty cool! There would be a lot of catches, like getting the 5V MSX and 3.3V Pi to play nice together, but if you can get past that you'd have a really unique device.

By Palver

Resident (64)

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04-11-2020, 22:38

Both fpga and raspi work at 3.3V, so no problem. Here an example, using a raspberry between an MSX-fpga and an usb keyboard (sorry, spanish).

By djh1697

Paragon (1509)

djh1697's picture

04-11-2020, 23:07

NetNomad wrote:

Have you seen this announced today?

https://www.raspberrypi.org/products/raspberry-pi-400/

It's an RPi 4 with an MSX-like form factor! This post was the first thing I thought of when I saw it, I wonder if you would be able to hook up an FPGA to this with the GPIO ports and be able to use the 400's keyboard in OCM mode. That would be pretty cool! There would be a lot of catches, like getting the 5V MSX and 3.3V Pi to play nice together, but if you can get past that you'd have a really unique device.

I had actually submitted a news report about this, however, this seems to have beat me too it! I suggest that a Pihat for the pi-400 as a horizontal cartridge slot? Should be interesting to make a new MSX?

By hamlet

Scribe (3411)

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29-12-2020, 22:17


With the known cartridge port for the GPIO, the result is an ergonomic posture for the Pi 400.

By Pencioner

Scribe (1294)

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30-12-2020, 02:01

I think it would be better with some kind of 40 pin flat cable (regular ATA IDE cable unfortunately can't be used because it's female on both sides but the cable can be built by someone with right tools). The picture looks great and fun but quite dangerous in use because of the angled connection, which makes some uncomfortable feeling about that ... Smile

By hamlet

Scribe (3411)

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31-12-2020, 12:31

Yes Ma'am!

By Pencioner

Scribe (1294)

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31-12-2020, 12:48

My world will never be like before Crazy

By DarkSchneider

Paladin (941)

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31-12-2020, 14:34

hamlet wrote:

Yes Ma'am!

Haha!

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