ByteDelight DIVMMC ENJOY! PRO ONE constant changing border colour/flashing

[8BitSC]

I recently bought a ByteDelight DIVMMC ENJOY! PRO ONE to replace my previous, dead MMC device.

When playing games from it however, the border constantly changes colour and is VERY distracting.

Do I have this device incorrectly configured?

Using the same .tap files on my Retroleum Smart card, there are no changing borders during game-play. Neither do I see flashing borders while playing, if I load from tap/tzx using a TZXDuino.

Retroleum smart card diagnostics indicate no issues with any of my Speccies. The Z80 M1 lines are diagnosed as working on all devices.

The border flashes regardless of the Spectrum I plug the DIVMMC device into.

Has anyone experienced this issue before?

Edit: I noticed it doesn't appear to support autofire either. Not that I'd use it much but if it's supposed to support autofire, I'd like to see it working.

[Seven.FFF]

Why aren’t you talking to Ben about this? A brand new device should be tested, supported and under warranty.

It’s definitely not normal for divMMCs to put anything on the bus for even numbered I/O port writes. Or to spam the bus when not asked to do paging operations, SPI operations or joystick reads by running programs. Those would be the only ways external hardware could convince the ULA to output different border colours.

[8BitSC]

I was merely wondering if anyone had experienced similar issues and checking around the Internet after posting here, it appears others HAD.

As it turns out, it matters the order in which devices are connected to the ZX Spectrum bus when using Ben's DIVMMC ENJOY! PRO ONE, even though it has a pass-thru connector.

It transpires that even when using two of Ben's OWN designs (Enjoy Pro One and his ZX-HD product; both of which have built-in pass-thru connectors) the DIVMMC should be placed BEHIND the video interface, otherwise problems can occur.

I'd been plugging a ZX-VGA-JOY into the BACK of Ben's DIVMMC as the ZX-VGA-JOY doesn't have its own pass-thru. It just seemed to make sense to plug-in the devices in this particular order, given the VGA adaptor has no pass-thru of its own.

It wasn't until I tried using a Currah uSlot to place the ZX-VGA-JOY BETWEEN the Spectrum and the DIVMMC, that the issue magically cleared up; and I only tried this after searching the web after posting here, and finding others had been unable to get their ZX-HD working correctly, if plugged-in behind Ben's DIVMMC.

It's not a faulty DIVMMC device and I resolved the issue without recourse to warranty claims by further using available resources to find a solution that didn't require me to send back a working device on a round-trip to NL.

Both devices are currently working as expected (no more border flashing), merely by changing both device's positions in the chain.

This was (I thought) a simple question. You can climb down from your high-horse now. Thank you.

[Seven.FFF]

High horse?! Where are you getting that from? Just trying to help.

[Seven.FFF]

It does make more sense now you said you’re using another external device that generates video output.

[8BitSC]

Why aren’t you talking to Ben about this?

Came across as "Why are you bothering us/me with this frivilous query".

Thank you for your input but as I said, it turns out it's NOT a faulty device.

Maybe I asked too soon and should've spent more time looking elsewhere for answers before bothering you guys.

[Seven.FFF]

Not a problem, I’m glad you solved it.

Ben does maintain a hardware cross-compatibility list but the ZX-VGA-JOY is not on it. I think it’s still worth talking to him so he can add your findings to the list.