Ninjabyte ZPX-128 (universal Z80 computer kit)

u/Dream of Omnimaga March 02, 2016, 03:39:51 AM

Unicode would probably take a lot of space. I would be ok with more limited character sets, but ideally, supporting multiple keyboard layouts would be better. It's hard to tell which one, though, since most people come from anywhere in the world. Will the RS232 connector be the same as TI-Nspires, or at least allow the use of the same interface?

u/DarkestEx March 02, 2016, 01:42:36 PM

Quote from: DJ Omnimaga on March 02, 2016, 03:39:51 AM
Unicode would probably take a lot of space. I would be ok with more limited character sets, but ideally, supporting multiple keyboard layouts would be better. It's hard to tell which one, though, since most people come from anywhere in the world. Will the RS232 connector be the same as TI-Nspires, or at least allow the use of the same interface?

Unicode was never in question. We will only support a selected range of keyboard layouts.
The connector is NO! RS232 port. Using it as one would very likely kill the ZPX128. It is just an expansion / update port.

u/Ivoah March 02, 2016, 02:06:43 PM

Quote from: DJ Omnimaga on March 02, 2016, 03:39:51 AM
Will the RS232 connector be the same as TI-Nspires, or at least allow the use of the same interface?

The Nspire doesn't have an RS232 connector. It has serial lines on the dock connector, but that's not the same as RS232

u/Dream of Omnimaga March 02, 2016, 03:24:50 PM

Ah I see. I wasn't sure what was the name.

u/DarkestEx March 06, 2016, 11:53:59 AM

I am currently working on the emulator for the platform so that you guys can test the platform and develop nice games and console applications before we have the prototype working and before you have to buy one.

u/Dream of Omnimaga March 07, 2016, 06:30:25 PM

Cool, I can't wait to see it in action.

u/DarkestEx March 09, 2016, 01:17:57 AM

We'll be getting rid of the PXA as it probably won't work. We'll now have an ARMv7ME based SMC (replacing the PXA) that runs at about 74 MHz and has 256 KB flash and 64 KB RAM. This means an upgrade in graphics but also that we have to switch from a octacore to a single core processor. But the interface between the Z80 will be many many times faster and updating the firmware can from now on be done using USB instead of a proprietary connector. Audio might be dropped if we can't afford the CPU so do that but we'll have to see about that one. Also we have new interfaces now such as a CAN bus and usb that might come handy for some people.
The price will increase by about 10€.

u/Dream of Omnimaga March 09, 2016, 01:26:18 AM

I am ok with a single core processor, since it's an old-school computer, after all. Just as long as drawing to the screen and some other things aren't crippled like on the CSE and Casio PRIZM. Audio isn't all that important unless the main target audience is gamers (but even if it is, I guess headphone support would do). Also good move by not sticking to a proprietary connector. It increases compatibility and makes it easier to purchase replacement cables.

u/DarkestEx March 09, 2016, 01:32:21 AM

Quote from: DJ Omnimaga on March 09, 2016, 01:26:18 AM
I am ok with a single core processor, since it's an old-school computer, after all. Just as long as drawing to the screen and some other things aren't crippled like on the CSE and Casio PRIZM. Audio isn't all that important unless the main target audience is gamers (but even if it is, I guess headphone support would do). Also good move by not sticking to a proprietary connector. It increases compatibility and makes it easier to purchase replacement cables.

Well the ARM processor is just the system controller that does video, keyboard, ram paging and some other stuff. The actual thing you program is the Z80. Drawing should be a lot faster with the new coprocessor / system controller, but we don't have any times yet. Audio would be dropped entirely if it doesn't work. Headphones would just make it worse. The issue is audio generation. We probably don't have any CPU time left to do audio at all. About the connector, I am not yet sure. The connector is a standard one, but used differently than usually. We'll probably still keep it (together with USB), as it adds a lot of extra functionality.

u/Dream of Omnimaga March 09, 2016, 01:33:39 AM

Ah I see about audio then. TOo bad. But I am ok with it.

u/Ivoah March 09, 2016, 01:35:23 AM

Can't you find some cheap audio synth chip?

u/DarkestEx March 09, 2016, 01:37:22 AM

Quote from: Ivoah on March 09, 2016, 01:35:23 AM
Can't you find some cheap audio synth chip?

Well sure that would work. Do you have any suggestions?
SPI interface would be great.

u/Ivoah March 09, 2016, 01:43:11 AM

Quote from: DarkestEx on March 09, 2016, 01:37:22 AM
Quote from: Ivoah on March 09, 2016, 01:35:23 AM
Can't you find some cheap audio synth chip?
Well sure that would work. Do you have any suggestions?
SPI interface would be great.

You could make your own with an attiny85 http://mitxela.com/projects/smallest_midi_synth

u/DarkestEx March 09, 2016, 01:46:19 AM

Quote from: Ivoah on March 09, 2016, 01:43:11 AM
Quote from: DarkestEx on March 09, 2016, 01:37:22 AM
Quote from: Ivoah on March 09, 2016, 01:35:23 AM
Can't you find some cheap audio synth chip?
Well sure that would work. Do you have any suggestions?
SPI interface would be great.
You could make your own with an attiny85 http://mitxela.com/projects/smallest_midi_synth

Well probably. I wonder maybe I could implement audio on the system controller itself using PWM and a timer.

u/c4ooo March 09, 2016, 02:57:42 AM

Maybe some simple 1 bit, on board, audio would be possible? I would suggest making the first prototype without audio, and then adding it in later if possible >_>