Sinclair ZX80 / ZX81 / Z88 Forums

Hi All

Got my MaxDuino v.1.66 by post yesterday.

Can anyone tell me the settings on the devise, for transferring *.p files from EightyOne to the Lambda?

I have the following options:
Baud Rate: 1200, 2400, 3600, 3850.
Moto Ctrl: On, Off.
ISXCzxpUEFSW: On, Off.

Have had a scope to the mono jack output, sharp 0-4,4 V signal.
(See attached file)

Have tried all Baud Rate setting, but with no luck transferring data to the EAR Lambda input with LOAD "" command.

Found most of the answers here:
https://hobbyretro-com.translate.goog/s ... x_tr_hl=da

Does anyone knows:
Settings for TSXCzxpUEFSW (inverting the signal) for use with the Lambda?

Mrtin and others did notice, that signals below 5,0V will not be able to load into the Lamda, as the Lambda appears to be a little deaf? Will try a audio amplifier to boost the signal up to 5V.

I will be back….

Hi again

Tried with audio amplifier to enable the Lambda to accept the incomming signal from the MaxDuino - No succes.
Tried all combinations in MaxDuino settings (Baud / TSXCzxpUEFSW) - No succes.
Tried several P. files (DSTAR-LAMBDA.P/FULL_lambda_16k.P/Game1_010_Lambda_2K.p/maanelanding.p/STARTREK.p/WALL-LAMBDA.P) - No succes.
Have tried to use a 9V power supply instead of a 12V - No change.

No flickering on the screen (indicating that data is beeing received), but:
With a active MaxDuino signal into the EAR input, when giving the command LOAD"" - half a second of flickering is seen on the monitor before the monitor is going black (blue in my case).
With no active MaxDuino signal into the EAR input, when giving the command LOAD"" - NO flickering is seen. So the EAR input have an effect to the Lambda monitor somehow.

Any suggestions?

So what is your voltage on the EAR input on Lambda when you load?

With a voltmeter it should be 2.5V, as that's average between 0V and 5V.

Maybe the scope will give an exact answer.

I'm no electronics expert, just saying what works for me.

Strange that you need an amplifier, as my Arduino output 0V or 5V each time.

mrtinb wrote: ↑Mon Aug 22, 2022 11:19 pm So what is your voltage on the EAR input on Lambda when you load?

With a voltmeter it should be 2.5V, as that's average between 0V and 5V.

Maybe the scope will give an exact answer.

2,0V meassured by a multimeter on the EAR centerpin.
2,5V meassured by a multimeter on ULA Pin2 (after the 10nF capacitor),

I measurred the capacitor to 114nF, so changed it to a 15nF without any changes to the ability to load programs into the Lambda.
I am about running out of good ideas, but somehow to verify weather the problem is on the MaxDuino or the Lambda would be nice.

I believe the MaxDuino should send 0V and 5V, showing as 2.5V with a voltmeter, when a P-file is sent. Try both with the Lambda connected and without.

mrtinb wrote: ↑Tue Aug 23, 2022 1:00 pm I believe the MaxDuino should send 0V and 5V, showing as 2.5V with a voltmeter, when a P-file is sent. Try both with the Lambda connected and without.

Hi Martin

Thx for your reply....

Measurred with multimeter.
DC voltage between Jack screen/ground to jack tip, from MaxDuino when disconnected from Lambda and playing a P-file: 1,1-1,3V
DC voltage between Jack screen/ground to jack tip, from MaxDuino when connected to Lambda and playing a P-file: 1,0-1,2V
DC voltage between Lambda Ground to Lambda ULA Pin 2 when connected to MaxDuino playing a P-file: 2,54V

Do you have 2,5VDC out from your "P-file playing device"?

Hi Jesper.

I've been thinking about making a video for you, for quite some time, to show how it looks to me, when I load a game on the Lambda 8300.

I hope you can compare the picture and voltages with what you have.

https://youtu.be/riutTeCjOLM

Hi Martin

Thanks for the fine video, showing the signal into the EAR input, i am not able to see the voltage level on the scope, but you read the maximum voltage to 4,4V.

I have tried the same setup with the MaxDuino (baudrate: 1200), and have an identic signal but with a maximum voltage at 3,8V.
Scope probe mounted onto the EAR input Jack.

I have attached pictures and a small video, showing:
- Maxduino, showing settings and P-file name (maanelanding.p).
- Scope picture showing the signal into Lambda EAR input.
- video showing the monitor when trying to load the maanelanding.p (a short flickering is shown for approx a quarter of a second)