Arduino-like Uzebox

[rlaw]

I'm working on a new Uzebox clone and I'd like to solicit some suggestions for the direction I should go.

I have a few ideas to consider:

• Add an FTDI chip so that we can make an Arduino-like Uzebox?
• Add an ATTiny2313 or similar chip so that there could be an on-board AVR-ISP?

The extra ATTiny would be the cheapest option and has the advantage that it wouldn't require the 644 to store any bootloader code. The FTDI chip could be interesting because it might allow for an Arduino-type programming environment to be ported to the Uzebox. Imagine being able to write Arduino sketches and quickly upload them over USB to the Uzebox! Of course it may require some major modifications to the kernel. I just throw this idea out in case anyone is interested.

What other changes/additions would you like to see in a new Uzebox clone?

[scuzz]

Well, I assume that you're going for having serial output from the Uzebox to an ftdi ft232rl, but from what I understand the uzebox itself has issues with the stability of the serial port due to the overclocking, which may be a problem.

That issue aside I think that adding the second chip to do in-circuit programming with a better bootloader (perhaps it could hijack the display and be a more fully featured SD-card "bootloader"?) would be pretty nifty. It would also free up some space on the main micro, and mean that people like me who don't own a AVR programmer would be able to develop for the console! Assuming you could get preprogrammed AVRs

[uze6666]

What about ethernet? It's been discussed many times in the past. You could have the traces for a Wiznet module or something like that.

-Uze

[rlaw]

The Wiznet module significantly increases the cost, which goes against one of my design goals. Perhaps I could add headers for it, but I believe it requires both a 3.3V and 1.8V power supply?

I didn't think of using the second chip as a bootloader, but I don't think it would be possible, at least with ATTiny2313. USBTiny takes up all the space on the chip. Maybe I could use a beefier AVR, but I'm not sure how a second chip could work as a bootloader for the 644. Anyone have any ideas on how this could be done?

[uze6666]

The Wiznet module significantly increases the cost, which goes against one of my design goals. Perhaps I could add headers for it, but I believe it requires both a 3.3V and 1.8V power supply?

Yeah, I thought about just the traces/header for it, an optional module. I was seeing this as a cool experiment feature for those who wanted to fork the extra cash (like myself ). Thought I did not know it required a separate 1.8v source.

-Uze

[rlaw]

I just had a look at a newer Wiznet module, the WIZ107SR. It seems to only require 3.3V. Would this be a good target module?

[scuzz]

Ack! Don't aim for that one! It uses rs-232 voltage levels! That means that the signal wires are, at best +5V to -5V (if it's EIA-232) or as bad as +12V to -12V! This can't be connected directly to your Uzebox without doing some pretty serious damage to the internal circuitry.

Unless you feel like designing in a max232 chip into your design (which is admittedly not very difficult, but more parts, more cost, etc), you should find a different wiznet module.

[rlaw]

I'm really unfamiliar with Wiznet, so are there any particular recommendations for use with the Uzebox?

Also, what are some probable use scenarios for an ethernet module? Online gaming? It seems the poor ATMega644 is already being pushed to its limit. Would there be space enough to implement online multiplayer games?

[uze6666]

I concur with scuzz, that module doesn't seem appropriate, notwithstanding the RS-232 voltages, using the UART could have it's problems with the 644P. The module that was mostly discussed previously was the WIZ811MJ. Some of it's features includes:

• Supports 10/100 Base TX
• Supports half/full duplex operation
• Operates from a single 3.3V source with 5V I/O signal tolerance
• Supports network status indicator LEDs
• Includes Hardware Internet protocols: TCP, IP Ver.4, UDP, ICMP, ARP, PPPoE, IGMP
• Includes Hardware Ethernet protocols: DLC, MAC
• Supports 4 independent connections simultaneously
• Supports MCU bus Interface and SPI Interface
• Supports Socket API for easy application programming
• Interfaces with two 2.54mm pitch 2 x 10 header pin
• Sells for about USD20$

When combined with a very simple protocol, the mega644 still has juice to handle net-based games using such modules. Since games have a relatively small amount of things moving at anytime, everything would take just a small part of single TCP or UDP frame that could be fired 30-60 times per seconds during vsync.

-Uze

[rlaw]

Wow, that thing has 40 pins. Have you assigned 644 pins to all the address and data pins of the WIZ811MJ yet?