#26E/F Z280 MPU Modul

[Kurt Pieper]

Here are my first test results with the z280 from Karl. I brought the C application LCD with TC74 (temperature module) to the z280.

At the moment the program xm does not work on the z280?
Is there a special version?

I take the detour with the sc126. My CF card for the z280 is loaded with the sc126

greeting

Kurt

[Bill Shen]

Hardware handshake is needed to run XM at 115200.  You can lower the baud to 57600 and XM should work at that speed.
  Bill

[Kurt Pieper]

Hello Bill,

I had already tried with a lower baud rate. That was also my first thought.

57600 baud one try. No do not go.

Should I change RomWBW?

Thanks for for info.

Kurt

[Wayne Warthen]

Hi Kurt,

On Thursday, May 13, 2021 at 8:49:16 AM UTC-7 kurt....@web.de wrote:

I had already tried with a lower baud rate. That was also my first thought.

57600 baud one try. No do not go.

Should I change RomWBW?

I don't think changing RomWBW will help.  Without flow control, even 57600 baud will probably not work.  I think 38400 baud should work, but if not, try even lower.  I would strongly recommend getting hardware flow control working.

For better or worse, RomWBW requires bank switching on every character read/written.  This constrains the transfer speeds.

-Wayne

[Karl Albert Brokstad]

Hi Kurt,

The problems you are experiencing may be due to floating !RFSH (pin 7) and !WAIT (pin 6) signals, and maybe also the AD0 line (pin 5).

Remove the max1232 and test if the problems disappear? I suspect the chip is outputting noise.

If so you can remedy that by adding a resistor (I have tested several values and landed on2k2) between those legs on the max1232 and the pcbs. 

Karl

[Karl Albert Brokstad]

Just another detail; only RX and TX is connected on the serial header, so you may have to turn off flow control.

I have not yet tested putting a resistor on the AD0 pin on the max1232, I will try that.

But I have tested and XM works with both max1232 inserted and removed at 115200baud, maybe a bit slow.

Karl

[Kurt Pieper]

Hello Wayne, hello Karl.

The combination of remove chip and mode com0: 9600 worked.

Karl, you can turn the Z280 board around.
I want to be sure that I hit the right solder joint in my attempt. I've already tried it with 2.2 KOhm. But I removed the chip again.

Thank you Karl, thank you Wayne. You deserve five stars.

Greetings from the Rhine.

Kurt.

Now I'm watching DFB Berlin final on TV.
I'm a Dortmund fan (Erlin Haaland from Norway is a great boy)

[Karl Albert Brokstad]

I have revised the board and added places for the resistors, but haven't ordered the PCB yet.

If someone else out there have a better solution to introducing !wait, !rfsh and AD0 signals  at startup I would be happy to try it out.

I feel the max1232 is a beast which needs to be tamed.

Karl

[Kurt Pieper]

Maschine (MCS80/Z80) ?

1. Test with the HI-TECH z280 option.

[Wayne Warthen]

On Thursday, May 13, 2021 at 11:02:03 AM UTC-7 Karl Albert Brokstad wrote:

I have revised the board and added places for the resistors, but haven't ordered the PCB yet.

If someone else out there have a better solution to introducing !wait, !rfsh and AD0 signals  at startup I would be happy to try it out.

The bootstrap circuit in Bill's ZZ80MB is pretty straightforward and has worked very reliably in my experience.  Perhaps you could consider using that circuit if Bill doesn't mind.

-Wayne

[Tony Nicholson]

For the Z280RC I added Z280 built-in console port polling mode I/O support

to XMODEM V2.7 - rather than using the BIOS console routines.

This works reliably for me at 115200 8-bit, Odd parity and 1 stop bit (the default).

Grab it from by GitHub at

https://github.com/agn453/Z280RC/blob/master/utilities/xm27z280.zip

Tony

PS. I don't use ROMWBW - so excuse any ignorance.  If the console support

for ROMWBW uses interrupts then you will need to add code to temporarily

disable them for the console UART while using this version of XMODEM's

built-in I/O.

[Wayne Warthen]

On Thursday, May 13, 2021 at 5:29:33 PM UTC-7 Tony Nicholson wrote:

For the Z280RC I added Z280 built-in console port polling mode I/O support

to XMODEM V2.7 - rather than using the BIOS console routines.

This works reliably for me at 115200 8-bit, Odd parity and 1 stop bit (the default).

PS. I don't use ROMWBW - so excuse any ignorance.  If the console support

for ROMWBW uses interrupts then you will need to add code to temporarily

disable them for the console UART while using this version of XMODEM's

built-in I/O.

Yes, RomWBW does use interrupts for handling the Z280 serial port.  Turning them off is not easy because RomWBW also implements Z280 system mode which prevents user-land code from making changes to system settings.  The Z280 serial port lives in system space, so user-land code will not be able to make the changes.  :-(

-Wayne

[Kurt Pieper]

Hello Karl,

thanks again for the pictures.

My change:

I soldered the MAX1232 according to the info.
It works with 19200 baud and most certainly with 9600 baud.

Otherwise module # 26E works without any problems. I was able to test it in continuous operation for about 4 -5 hours. My software both BASCOM (Fibu) or Assembler Z80 (vocabulary trainer spanish) and HI-TECH Z280 the program LCDTC74.C with the SC137 module (I2C) work perfectly.

The helpful information helped me.

greeting
Kurt

[Karl Albert Brokstad]

Hi Kurt

That's great news. I also added a resistor to the AD0 / pin5 line, maybe it became more better.

Anyway, here is the latest revision (not ordered or testet yet) which I hope will make this module more robust.

The module is becoming crowded.

Karl