Re: [stella] A26 Maxicart

[David Galloway <davidgalloway@xxxxxxxxxxxxxx>]

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.
>
> -paul

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