Sinclair ZX80 / ZX81 / Z88 Forums

mrtinb wrote: ↑Thu May 25, 2017 2:39 pm Looking forward I would appreciate just a P-file with a number, that contains both firmware for USB and EEPROM. Then there's no need to focus on which firmware fits together. Maybe if a test for the CPLD-version is in the software as well, it's just a LOAD and RUN.

No that's not possible this way or say to complicate to realize. The firmware for the USB chip is about 200kByte and should be loaded from the USB disk. On the other hand, the new flash rom works with older USB firmware as well. What is installed is written on screen (version of ZXblast and version of USB driver). You can not see what the CPLD's revision is inside but older will work as well except some special features rarely used.

It is recommended to have the actual latest CPLD with date 05/2017 for future releases/updates. It is possible to buy this chip from me for EUR 3.00 only which may be cheaper than sending the old chip back. It is unlikely, that there will be future CPLD updates or will affect only some minor special features like memory paging or similar. Anyway the CPLD is nearly full, 63 of 64 macrocells used, so no new features to add. Some bug showed up with the implementation of software updates but this is solved now.

will there be an option to add usb joystick support?

Yes - I think so in future. There might be some incompatibility depending on how the programs read the keyboard. If INKEY$ is used either from BASIC or called from assembly it should work. If assembly programs do directly read port $FE there might be problems. Well - we will see.

has anyone had a problem with 1.1c recognising there 512k ram version?

Using zxblast with my zx80 clone in zx81 mode.

Hi

Is there any progress on fixing the firmware, so the file manager works with all directories. Most directories gives "Not found" when selected. Typing in the path works. It seems the USB firmware needs a reset with "//" quite often.

Is it correctly understood, that Double Shift - "Command" only works in SLOW mode?

Is it correctly understood, that M1NOT will arrive with a later firmware?

Sorry still didn't find much time to program software.
As I work independently and overtook a complete business this year my personal time is mostly exhausted.
Hopefully will get better in november and december.

About your questions:
Only during SLOW mode the firmware is active to listen to any double shift commands.
This is technically not possible during FAST mode.

The M1NOT is a software feature but requires the latest CPLD, maybe a CPLD upgrade is needed.

I appreciate your efforts very much, and I know how sparse time can be. Thank you for your answer.

I'm curious Karl, how can M1NOT be achieved without modifying the ZX81 internally ? surely the ULA will still respond when A15 is high and it is M1 cycle and try to do a video cycle ?

Regards Andy

For half a clock cycle A15 is overridden during M1 in the memory area $8000-$BFFF. As the CPU outputs are not very strong and this a rare situation it wouldn't harm the Z80.