Search found 44 matches
- Sun Apr 09, 2017 10:36 am
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
Ah probe, 1X - 6Mhz, 10x - 100Mhz so the signal was being heavily attenuated. I've never had a scope before so you'll have to forgive me. However I have found some more useful information. The UMDK's bridge board triggers signals at ~2v (for me anyway), probing /OE (on both the MD side and the FPGA ...
- Fri Apr 07, 2017 9:36 pm
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
It's your cheap (relatively) chinese jobby - Hantek DSO5102P, but it comes under a few different names. For sure the probes won't be the best.
- Fri Apr 07, 2017 6:01 pm
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
What Mega Drive are those voltages from?
I've just checked on a Mega Drive II and I'm seeing EDClk go between 0-4.5V, is it possible that on some Mega Drives the signal is too weak?
I've just checked on a Mega Drive II and I'm seeing EDClk go between 0-4.5V, is it possible that on some Mega Drives the signal is too weak?
- Wed Apr 05, 2017 6:28 pm
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
So here's some shots of EDClk, triggered as it switched to 10.6Mhz On a regular cart: http://www.skgenius.co.uk/FileDump/MD_0.png On UMDK: http://www.skgenius.co.uk/FileDump/UMDK_0.png And if you look in this pic you can see clearly that there's a repeating pattern running through, which repeats at ...
- Tue Apr 04, 2017 10:44 pm
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
So for today's pokes and prods I was using one of my Mega Drives which is modded with phono jacks for audio + composite so it doesn't need any special cables (the composite is pinched from the DIN so there's nothing fancy there, actually the audio jacks are currently disconnected so it makes the who...
- Mon Apr 03, 2017 6:58 pm
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
Just found an interesting artefact before looking into this more betterer. If i switch the console from NTSC to PAL while it's running, then it doesn't crash when playing the SFX. Or at least MJ's Moonwalker doesn't, although the game runs slow if you switch it when running.
- Mon Apr 03, 2017 4:28 pm
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
Yeah, I've put this together myself.
Doing a trace is my plan for this evening, along with checking the expected behavior in an emulator
Doing a trace is my plan for this evening, along with checking the expected behavior in an emulator
- Sun Apr 02, 2017 1:59 pm
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
Tried on my other MD1 (same board, but with a different colour silkscreen) same issue
- Sun Apr 02, 2017 12:48 pm
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
Re: MD hangs after playing any PCM file
Silkscreen says IC BD M5 PAL, checking out http://segaretro.org/Mega_Drive_PCB_revisions it looks like a VA6
- Sun Apr 02, 2017 11:55 am
- Forum: UMDK
- Topic: MD hangs after playing any PCM file
- Replies: 69
- Views: 96593
MD hangs after playing any PCM file
When playing a rom through the UMDK it all works fine until some pcm type sound file is played and then the game hangs. So if we take the common example of Sonic 1, as soon as the game starts you get to hear the wonderful "SEGAAA" sound clip, after which the game crashes (Illegal instruction $00071F...
- Wed Mar 29, 2017 8:31 pm
- Forum: UMDK
- Topic: USB device not recognised (CY7C68014A woes)
- Replies: 5
- Views: 8004
Re: USB device not recognised (CY7C68014A woes)
So I got an oscilloscope (always nice to have an excuse to buy some new gear), the crystal is oscillating fine (with the 22pf caps) It seems that the reset pin is outputting 3.3v (which for sure is not supposed to happen) I disconnected the resistor at R2 to verify, and sure enough it's getting some...
- Sun Mar 19, 2017 11:25 pm
- Forum: UMDK
- Topic: USB device not recognised (CY7C68014A woes)
- Replies: 5
- Views: 8004
Re: USB device not recognised (CY7C68014A woes)
They've already been replaced.
Increasing the capacitance gets the crystal going but it's unstable. I'll have to pick up some different values and see what it needs.
The boards are identical though, I can only guess that the working board is just scraping by.
Increasing the capacitance gets the crystal going but it's unstable. I'll have to pick up some different values and see what it needs.
The boards are identical though, I can only guess that the working board is just scraping by.
- Sun Mar 19, 2017 10:45 pm
- Forum: UMDK
- Topic: USB device not recognised (CY7C68014A woes)
- Replies: 5
- Views: 8004
Re: USB device not recognised (CY7C68014A woes)
All voltages match on the boards, resistors are correct. Quite by chance I've managed to replicate the behaviour on the working board. If I measure the voltage at the crystals leg and hold the probes long enough (5-10 seconds), that stops the crystal until the device is reset. The leg now shows as 3...
- Sun Mar 19, 2017 6:43 pm
- Forum: UMDK
- Topic: USB device not recognised (CY7C68014A woes)
- Replies: 5
- Views: 8004
USB device not recognised (CY7C68014A woes)
I've been putting together a couple of boards but one of them is giving me jip. One of them enumerates properly and the usb device shows up, the other does not. There are no dry joints (that I could find, obviously). There are no shorts between any of the pins on anything anywhere, i've looked with ...