Raspberry pi loader

Using, learning, programming and modding the Gigatron and anything related.
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Serion
Posts: 6
Joined: 18 Jul 2020, 23:42

Re: Raspberry pi loader

Post by Serion » 20 Jul 2020, 00:22

at67 wrote:
19 Jul 2020, 03:12

Welcome and congratulations on getting the Gigatron up and running; it really is a testament to the attention to detail that Walter and Marcel put into the kit's construction and manual that allows so many first time success stories.
Yes! Without a doubt! I was amazed at the quality and time they put into building these kits. And I'm so, so happy I just barely squeezed in to get one of the last few kits sold! (I'm usually never this lucky!)

And I'm floored at all the time you took to help me out with this loader!! Thank you, thank you! I'm VERY excited to get started! I swear I feel like a kid again.

One question before I start down this path... Is this the easiest/best way to build a loader? I'm trying my best to sift through all the great posts on here and I've seen mention of a SD card loaded?? And also an updated ROM that's in beta. (BTW is anyone here able to burn one of these ROMs for me. I'd happily pay for all expenes and their time!)

Thanks again for the super warm welcome!

at67
Posts: 184
Joined: 14 May 2018, 08:29

Re: Raspberry pi loader

Post by at67 » 20 Jul 2020, 00:42

Serion wrote:
20 Jul 2020, 00:22
One question before I start down this path... Is this the easiest/best way to build a loader? I'm trying my best to sift through all the great posts on here and I've seen mention of a SD card loaded?? And also an updated ROM that's in beta. (BTW is anyone here able to burn one of these ROMs for me. I'd happily pay for all expenes and their time!)
Given that you have an RPi available, I would say using it is probably the easiest way of uploading to your Gigatron; but there are a lot of unknowns with the RPi solution as I mentioned in my previous post.

There are many Arduino based solutions, with Norgate's Pluggy Reloaded being the most comprehensive one. Norgate created a solution that supports PS2 keyboard, controller and SD card, that thread is here:
viewtopic.php?f=4&t=169

You can source and buy all the parts and then build it yourself, or ask Norgate if he has any remaining stock left and he will ship you a kit that you have to solder, (takes 10-15 minutes tops).

There are many people on the forums that are capable of programming ROM's, but given the current shipping situation unless you find someone close to you it might be easier to purchase a UV eraser and programmer and do it yourself, (which would probably be better in the long run if you want to change/upgrade ROM's multiple times). You can follow this thread for programming ROM's under both Linux and Windows and for the hardware/software that you need:
viewtopic.php?f=4&t=239#p1530

Serion
Posts: 6
Joined: 18 Jul 2020, 23:42

Re: Raspberry pi loader

Post by Serion » 20 Jul 2020, 17:35

at67 wrote:
20 Jul 2020, 00:42
There are many Arduino based solutions, with Norgate's Pluggy Reloaded being the most comprehensive one. Norgate created a solution that supports PS2 keyboard, controller and SD card, that thread is here:
viewtopic.php?f=4&t=169

You can source and buy all the parts and then build it yourself, or ask Norgate if he has any remaining stock left and he will ship you a kit that you have to solder, (takes 10-15 minutes tops).
Thank you again -- you're a wealth of information and are so kind to share it!

Norgate's solution sounds amazing. I'm going to check that out now.

All of this is just mind blowing. Growing up in the 70's/80's, I had probably all the same 8-bit machines most folks here had TI, various Commodores, etc. And to think this is something that could have been built before the first one of those ever hit the shelf AND out perform every single one for years and years to come -- truly amazing!

klf
Posts: 4
Joined: 10 Jan 2019, 22:48

Re: Raspberry pi loader

Post by klf » 23 Jul 2020, 11:31

at67 wrote:
19 Jul 2020, 03:12

So the first thing to do is to wire up the RPi's GPIO header to a female DB9 connector. You will need some sort of multi-conductor cable with at least 4 unique wires, (I would personally use a strip of ribbon cable for testing purposes and then clean it up later once it's running).
Be careful, the Raspberry's 3.3 V inputs are not really 5 V tolerant. The 68R resistors in series with SER_PULSE and SER_LATCH provide some current limitation but they are no level shifters. YMMV.

at67
Posts: 184
Joined: 14 May 2018, 08:29

Re: Raspberry pi loader

Post by at67 » 23 Jul 2020, 16:47

klf wrote:
23 Jul 2020, 11:31
Be careful, the Raspberry's 3.3 V inputs are not really 5 V tolerant. The 68R resistors in series with SER_PULSE and SER_LATCH provide some current limitation but they are no level shifters. YMMV.
Big oof, I assumed from xbx's original post that the GPIO inputs were either 5v tolerant or 5v inputs given that he didn't mention any level shifting in his post or code. He did mention that the RPi was unreliable when uploading to the Gigatron, I wonder if this over-voltage on the inputs was causing some sort of parasitic latch up, (temporary or permanent), and that he never realised.

I spent a good 30mins researching the RPi's GPIO electrical characteristics and talk about an underwhelming representation of good documentation :/

Anyway thank you for the warning, I've updated my post.

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