Re: [stella] A26 Maxicart

Subject: Re: [stella] A26 Maxicart
From: David Galloway <davidgalloway@xxxxxxxxxxxxxx>
Date: Sun, 17 Oct 2004 13:22:39 -0700
Paul Slocum wrote:

The 2600 clone that's going to come out will have a USB interface also and should support all cart types so people might want to get that too (I hope that shows up before Xmas).

Weird that the USB interface on the Maxicart is so slow. It sounds like it's 26 seconds to load a 32k file?! (And odd that they give 32K as an example when it doesn't support F4?) It takes about 3-4 sec on the Cuttle Cart II over serial.


One can only speculate but from the design spec (which doesn't seem to include a embedded processor) perhaps the code to program the flash is running on the PC side and using the USB port as a slave device, instead of quickly downloading the entire 32K and having a CPU on the cartridge run the flash algorithm. Doing it this way has the potential for the developers to encounter some handshaking pitfalls if they don't quite understand USB or Windows driver programming. In any case, something grossly inefficient is happening here. At the low end of the USB 1.0 spec we have a throughput of 1.5 Mbit/s. This should allow a very decent download time for 32K (0.25 Mbits) . I would like to acknowledge that the overall cart programming time has to include the flash programming time, which can also vary greatly depending on how well the code is written and whether the code can read back the data (verify) or just has to wait for the worst case timing before moving on.

- David

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