ZX-128A4U

rich · Post by **rich** » 04 February 2019, 19:49 PM

Any one have a pcb for this 44-pin TQFP chip with the necessary aux circuitry?

Thanks
Richard

Post by **dkinzer** » 05 February 2019, 11:16 AM

I don't know of any boards specifically for the ATxmega128a4u other than our ZX-24u board. What kind of board are you looking for?

If you decide to design your own PCB you'll find an overview of the necessary additional circuitry in Appendix K of the ZBasic Reference manual.

www.zbasic.net/doc/ZBasicRef.php?page=221

Also, the schematic for the ZX-24u (which uses the same PCB as the ZX-24x) can be found at the URL below.

http://www.zbasic.net/doc/ZX-24x_Schematic.pdf

rich · Post by **rich** » 06 February 2019, 13:27 PM

I was not very clear.

The ZX-24 series inverts the TX and RX data so they need to be driven with real RS-232 signals.

As opposed to non inverted TTL signals which is what two of the USB serial adapter that i have do. I think most of the new ones do not invert the TTL signals so they are compatable with Arduino.

So i was wondering if there was a board that brought out all the chip I/O pins and worked with TTL serial.

Also all the Zx-24 parts tie pins together for the larger pin count devices. I wanted to use all the I/O pins available for a device.

I was not clear at all.
Apology.

Richard

mikep · Post by **mikep** » 06 February 2019, 17:41 PM

There isn't a board with everything you want. The closest would be something like the MT-DB-4. You would have to attach a USB-TTL Serial converter to the RX/TX. You would also need to program your own ZX bootloader/firmware and figure out the pins to use for everything.

rich · Post by **rich** » 07 February 2019, 9:27 AM

That is what i had in mind.

Another option is to modify a ZX-24 schematic with all the pins coming out and the serial interface non-inverting.
Design a PCB and get them built and populated.

Maybe Elba would want to do that?

Richard