15 replies to this topic

[Reiner Vogt]

Hi all,

i am looking for a possibility to save fx5800p programm/fmla data into a pc
or an alternate storage medium.

Does the interface which one be supposed to work only in the mode from the same
calculator to calculator (fx5800p), is this usable also differently - for example e.g.
into another processor like Microship PIC oder ATMEL-CPU, or a ser. Port from or
to a PC?

A little screenshot :



Has anybody an idear or know a wiring diagram of that fx5800p interface port?

regards,
Reiner V.

[ECE]

Hi Reiner Vogt,
I?m not sure I?ve understand you well; in the title of the post you wrote ?Interface from 1.5v to 5v. TTL?.
Are you saying that the communication signal level of the fx-5800p is 1.5v? Did you measure it or read it from a specification document?
If so, then you need a level converter, which is simple to design and build, also you need a s/w interface for the PC. I can help with the h/w if I can get enough information about the output signal.

[Reiner Vogt]

I?m not sure I?ve understand you well; in the title of the post you wrote ?Interface from 1.5v to 5v. TTL?.
Are you saying that the communication signal level of the fx-5800p is 1.5v?

Hi M.Yasser,

so I believe that the voltage level of the interface is 1.5v - because the
battery power of the fx5800p is only equipped with 1 pieces of AAA (LR03).

i'm sorry i havn't a specification document of my calculator, do you have it? it will
be help me by the development of an little interface...

On the manufacturer site i havn't found anything specification document about
the casio fx5800p calculator.

I can help with the h/w if I can get enough information about the output signal.

It will be fine when you can help me with that level-interface. I want to measuring
the voltage on the 3-wire (i guess it is a serial communication) - when i got an
result i will post it here...

so long,
Reiner V.

[Reiner Vogt]

Hi M.Yasser,

it looks like that the using power of that interface is around 0.5v - 0.7v as a high signal,
so my cheap Oscilloscopes told me that...

Knows anyone some data sheet about the fx-5800p communication interface?

so long,
Reiner V.

[ECE]

it looks like that the using power of that interface is around 0.5v - 0.7v as a high signal,
so my cheap Oscilloscopes told me that...

Dear Reiner Vogt,

The 0.5v-0.7v level is not sufficient for noise immunity, I guess the measurement was inaccurate.

Please try the followings,

1. mark your 3-wires (photo supplied in the first post); Tx, Rx and GND.

2. On the 2.5mm stereo jack, tip=Tx, middle=Rx, base=GND, your marking should confirm with it.

3. Connect the 2.5mm stereo jack to the calculator and the wires marked GND to the oscilloscope ground and Tx to the measuring terminal of the oscilloscope.

4. Put the calculator in the transmitting (send) mode, pretending to send data.

5. Observe the signal on the oscilloscope; it should be a square wave of some amplitude. Measure the amplitude of the signal. You may need to adjust the scale and the time base of the oscilloscope to get a correct reading.

Unfortunately, I couldn?t get access to any data concerning the fx-5800p.

Regards.

[Reiner Vogt]

...Observe the signal on the oscilloscope; it should be a square wave of some amplitude. Measure the
amplitude of the signal. You may need to adjust the scale and the time base of the oscilloscope to get a
correct reading.

I'm sorry, nothing to see - one signal goes from high to low, the other one from
low to high...and than the calculator say: transmission timeout (or euqal in receiving mode).

Unfortunately, I couldn?t get access to any data concerning the fx-5800p.

Thats also my problem - no information available...

[ECE]

I'm sorry, nothing to see - one signal goes from high to low, the other one from
low to high...and than the calculator say: transmission timeout (or euqal in receiving mode).

Yes, this is the hand shaking signal. The calc. is waiting for response from the receiving Rx, so you must emulate an acknowledge signal. I don?t know the level of that signal. I?ll try some search about it. I?ll post if I found something useful, you may try to put the calc. in the receive mode and measure the Rx signal to find out.

[Reiner Vogt]

Yes, this is the hand shaking signal. The calc. is waiting for response from the receiving Rx,
so you must emulate an acknowledge signal. I don’t know the level of that signal.

Hier are a overlayed picture of the oscilloscope mesurement:



The volts/div is set to 50mV.

so long,
Reiner V.

[Reiner Vogt]

Hi all,

in consideration of non existing or available techn. Information about the fx-5800p
i have stop now my personal project in fact of too little chances to reach the target.

Thanks to everyone who wants to help me...

so long,
Reiner V.

[ECE]

Dear Reiner Vogt,
Iam sorry you are disappointed, let us give it another try; have you set your oscilloscope to DC voltage-> The amplitude (0.025v.) is very small!!
I still think that a small modification to http://www.stormbase.net/images/56.png will work for you.
Please don’t quit easily.

[Reiner Vogt]

Please don’t quit easily.

Hi M.Yasser,

thanks a lot for your great idears and help to my little "like to have" project. Today,
i have sold my fx-5800p calculator - Still have been able to obtain a very good price...

I think I want to buy another pocket calculator for me in the next time. I don't know
which model, perhaps "Casio FX-9860 G SD" yet - Would this be the right choice ->

[ECE]

Yes, I think its a great choice.
Good Luck.

[kucalc]

Well it depends on what you are going to use it for. Other good looking alternatives are HP-200LX, ClassPad, etc.

[ECE]

Hi,
If the signal is oscillating between 0v. and 2.5v.,then I assume that it is half the TTL voltage level. Thus a simple level converter may be implemented using a comparator for the transmit part of the signal and a clipping circuit; may be implemented using a zener diode for the receiving part of the signal.
The MAX232c accepts (0-0.8)v. as logic zero and (2-5)v. as logic one. Between 0.8 v.and 2v. is undefined.
As a first trial, put a reference voltage of 0.4 or 0.5 to the –ve terminal of the comparator and solder the transmitted (Tx) signal to the +ve terminal of the copmp. Supply the comp. from the same 5v. regulator of the circuit. The o/p of this circuit will be 5v. for each i/p greater than 0.5v and 0v. otherwise.
For the receiving signal, a zener diode of 2.5v. may be used to clip the logic one (5v.) to 2.5v.
From here you may start your experiments , adjusting the reference voltage of the comp. and the clipping zener until you have a stable readings.
Another helpful thing to do is to havet two units, connect them with SB-62 cable and attach the probes of the oscilloscope to the Tx,Rx,GND wires. Observe the levels of the Tx,Rx with respect to GND.