Read joystick port

[+Philsan]

I have a DCF77 receiver, without drivers, that connects to joystick port.

I think it transmits data to joystick pins 1 or 2 or 3 or 4.

How can I read those values with a Basic program?

[Irgendwer]

I would guess that only one pin is relevant for the data transmission (serial protocol) and one is ground and another vcc.

The 4th pin is normally used as kind of chip select, no idea how this is realized with you module.

 

The data on the serial pin is received during the 21th till 58th second and belongs to the following minute.

(To fetch the correct start some receivers need some minutes.)

You should be able to watch the changing data on the port with a simple:

 

10 ? PEEK(54016):GOTO 10

 

The interpretation of the serial data is a bit more complicated.

To get an impression you can find f.e. Arduino C-source code here: https://github.com/thijse/Arduino-Libraries/downloads

 

You may also noticed already that for a "real working" watch, you need to update/count the seconds independently from the receiver, as the receiver only provides the "time-base" and "sync" information.

[+Philsan]

Thank you very much.

 

In fact I have this device

http://atariage.com/forums/topic/276485-der-dusseldorfer-ei-atom-uhr/

and I would like to know if it works.

I fear it doesn't work because yellow light should turn on every second.

It turns on if I move joystick cable, so I think some connections are loose.

With PEEK(54016) I get a value of 255. I get 254 when yellow led is on.

 

CharlieChaplin found a PD program for Atari that should be compatible with this device:

https://www.conrad.ch/de/dcf-empfaenger-modul-641138-passend-fuer-serie-c-control-641138.html

At least is what I hope, after having read what is written here:

https://ralfzimmermann.de/dcf_hard/

The program doesn't work with Dusseldorfer Ei (or Ei is broken).

Today I will receive Conrad DCF77.

 

I attach Atari program.

I think time check is made by an assembly routine in lines 8410-

 

DCF-77.txt

[Rybags]

The ASK signal is 1 bit per second so it takes an entire minute to receive each data packet.

 

I assume that the device probably only provides the AM signal, fair chance the Atari wouldn't be fast enough to decode the raw PM stream.

 

The end of minute marker is what's needed to be looked out for - during that second there's no change in amplitude.

I pasted the relevant Data sections into Altirra and ran it to generate the code - it seems to be using system countdown timers so would be sensitive to PAL/NTSC. Likely of course it was created on a PAL machine.

 

If the device is just creating a raw 0/1 signal for the Atari based on the amplitude of the DCF77 signal, then you should see a duty cycle of 80-90% per second with the zero level duration representing a 0 or 1. And 100% duty cycle representing the last second of the minute.

[Irgendwer]

At least is what I hope, after having read what is written here:

https://ralfzimmermann.de/dcf_hard/

The program doesn't work with Dusseldorfer Ei (or Ei is broken).

 

AFAIK Ralf Zimmermann's app should work with the hardware. If not, I guess the module is broken - but have you really waited long enough if the receiver syncs?

Like said, this needs often some time and in southern Switzerland I would at least wait 10 minutes to check if the hardware is able to sync and starts transmitting to the computer...

Edited August 24, 2018 by Irgendwer

[+Philsan]

How do you know I live in southern part of Switzerland? Ah ah. I hope to see you again..

 

I found it's not a problem of joystick cable bending but it's receiver position that matters.

 

Instead of A8 program I tested Ralf Zimmermann ST program and here's what I get.

 

 

So you're right, Dusseldorfer Ei is compatible with Conrad's DCF77.

 

I think the signal is low here or perhaps the receiver isn't very good.

 

I will test Conrad's device (I am working on it... http://atariage.com/forums/topic/282233-cx40-joystick-pcb-pinouts/?p=4098804)

[Irgendwer]

 

 

How do you know I live in southern part of Switzerland? Ah ah. I hope to see you again..

 

Probably next year...

 

I found it's not a problem of joystick cable bending but it's receiver position that matters.

 

Yes, it's f.e. important that the antenna is in horizontal position and perpendicular to the direction pointing to Frankfurt.

Good luck with the module from Conrad!

[Rybags]

Interesting stuff - turns out there's other places around with similar timeclock signals.

 

But no luck in my area, nothing here... though it's mostly obsolete since GPS receivers have become affordable.

[+Philsan]

After many attempts, yesterday night, the Atari ST program read the time from my Düsseldorfer Ei Atom-Uhr.

That device has a led, so it's easier to see if there's the signal.

Unfortunately where I live the signal is very weak so doing tests is a nightmare.

The attached A8 program didn't work.

 

No luck with Atari ST or A8 programs together with Conrad's DCF77 receiver.

As written, without led and with a weak signal, it's impossible to do tests.

 

If someone with coding and hardware skills is interested in doing tests, I could send him Conrad's receiver.

DCF-77_Funkuhr.ATR