nesdev.org

Hi all, I need some info from PowerPak users.
I've been working on a soft & hardware project, a version of Vegaplay with midi clock sync input. The hardware is a Midi sync to 24 ppqn PIC circuit feeding the player 2 port. The circuit is powered from the port, but I have run mine from an external PSU as well. I use an INL mmc1 cart and a friend is testing with a PowerPak; but we have run into a snag.
On my setup all works well, but the PowerPak hangs at the boot with the circuit plugged in. If it is plugged in after booting and rom selection, it works as expected.
I suspect that the problem is too much loading on the Vcc rail booting the NES, the PP and the PIC all at once; or a noise issue. The only other thing that could be a cause is some port reading during the PP boot. To the NES the circuit is a 4021 and during the PIC's init there may be a few uSec when the PIC-to-4021 pins are holding random values. This would only affect the PP if it's doing reads to port 2 during this time period. I don't know too much about the PP so I could use advice.
I have suggested some tests to narrow down the issue; using ext power to his circuit, sequencing the power-up delaying the PIC boot. But the distance and time demands on my friend has slowed down the alpha testing. So any advice with the PowerPak's booting would help.
Thanks,
Yogi

Most of the PowerPak's modules, including the intro screen one, include their own controller reading routine that reads both controllers. This is very easy to patch out, if you need it.

Thanks NoveSquirrel I'll pass your patched mapper along for testing. Very strange, any idea why the PP reads port2 during boot?
I'll have to dig into it's manual I guess.
Yogi

yogi wrote:Very strange, any idea why the PP reads port2 during boot?

I assume it's for letting player 2 operate the menus too.

I suppose, but the weird part is the 6502 takes quite a long time to init compared to the PIC, so I would think the outputs from the PIC would be settled by the time the 6502 would be ready to read ports (?) When the PIC is up and waiting for incoming Midi ticks, the interface is the same as having a pad connected without pushing any buttons.
Anyway, I can't produce the problem with a flash cart, so will have to rely on the 'long distance' testing to find a solution.
Hoping someone has some idea of the current draw for the PowerPak during it's setup.
Yogi