Using the Serial Port on the HP 50g Graphing Calculator

[Ranothil]

Hi Everyone,

I have another question. I want to use the Serial Port on the HP 50g to communicate with another device. The device is called the MFJ-1214PC. What it does is accept text and commands through a 9pin Serial Port and converts the text into an audible Morse Code/RTTY sound. It also decodes Audible Morse Code and RTTY signals from your radio and displays them as text on your computer. The program that commands the MFJ-1214PC was originally written for an IBM PC for the MS-DOS Operating system. The HP 50g graphing calculator meets the system requirments for the most basic version of the program. I wondered if there was an MS-DOS emulator written for the HP 50g that would allow the HP 50g to become the computer in this situation, or if the program could be rewritten and ported to the HP 50g. If it could be rewritten, what programming language do you think would be best suited to this type of application (if it is even possible?) i.e. UserRPL, SystemRPL, or Assembly. Keep in mind that I am a complete beginner with the HP50g and haven't ever programmed with it yet. I will include the manual of the MFJ-1214 PC as an attachment so you won't have to search for it. Thanks in advance for your help!

~Zekelegge~

[BartdB]

Hi,

Please note that the serial port "as is" on the 50g is not a standard serial port.

See the following write-up:

http://www.allenwan.com/hpcalcserialcable/

.

[HP-MACH]

Hi!, zekelegge:

Please, see ... http://h10010.www1.hp.com/wwpc/us/en/en/WF05a/215348-215348-64232-3732525-3732524-3732522.html?dnr=1

And ... http://www.educalc.net/1518486.page

Or ... http://www.educalc.net/1520485.page

Too ... http://www.educalc.net/1679489.page

Note: This device, support too, HP50G Graphing calculator's.

[Ranothil]

Thanks for your help so far! 🙂 Since this device accepts 8 Pin Din connections, do you think I could use a 9pin Din to 8Pin Din converter in order to connect the MFJ-1214 PC to this device, which would then feed information to and from the calculator?

~Zekelegge~

[Ranothil]

Yep! If I use the device that Miguel Angel Caporalini is suggesting, then I wouldn't need an adapter, but I have already purchased that adapter described on the webpage!

~Zekelegge~

[pin224466]

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@zekelegge wrote:

Yep! If I use the device....

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....ummm.... what exactly are you planning to connect to what???

are you referring to connecting this device to the 50g:

http://www.radioworld.co.uk/catalog/mfj-1214pc_data_controller-p-3041.html

[Ranothil]

I am planning to connect the MFJ-1214PC to the HP50g either via the HP Stream 400 or through the HP 50g Serial Port. I am afraid that the HP Stream 400 thing won't work with it since it says that it is only compatible with certain probes, but if you guys think that it will work, then I will purchase one and give it a shot!

~Zekelegge~

[pin224466 · Accepted solution]

If I understand (from my brief review) the output of the  MFJ-1214PC decoder box, this box provides a serial ouput to the computer.  The computer (the 50g in your case) will have software to read the serial message and then convert that to an output for display.

BartDb gave you the correct answer.

A serial cable with the correct level shifter and inversion to handle how the 50G presents a RS-232 signal to the outside world is the right solution.

However, make sure that the serial packet ouput from the decoder box can be understood by the 50G... baud, bits, etc.   (you have the decoder box manual so you will have to look that up)

the streamsmart is not a serial port aggregator.

in other words, those qty 4 DIN connectors on the front do not accept rs-232 serial input and then pass it on to the 50G.

i'm not a streamsmart expert, especially since info on these boxes is rare to find.  Even more rare are the probes.

however, my understanding is that the 4 connectors are for Analog to Digital conversion from the probes.  The streamsmart functions like a 'data logger' in that it sees the probe input, A/D converts it, then sends it to the 50G (or computer via USB port).

In addition to Bart's solution, there was another forum poster named Tiwag that created a serial cable and posted a schematic of the cable.  This information can be found here:

https://groups.google.com/forum/?fromgroups#!searchin/comp.sys.hp48/serial$20port/comp.sys.hp48/ltca...

further, to see a programming example of using the 50G serial port, you can reference the following GPS data collection program from hpcalc.

http://www.hpcalc.org/details.php?id=7105

it is written in userrpl so can be cross-referenced with the Advanced Users Reference for syntax translation.

it looks like the primary sub-program of concern for the comm to the gps is in the file "GPS>"

[pin224466]

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@zekelegge wrote:

If it could be rewritten, what programming language do you think would be best suited to this type of application (if it is even possible?) i.e. UserRPL, SystemRPL, or Assembly. Keep in mind that I am a complete beginner with the HP50g and haven't ever programmed with it yet. I will include the manual of the MFJ-1214 PC as an attachment so you won't have to search for it. Thanks in advance for your help!

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there really is not a valid answer to that question since no-one has access to the software or for that matter the system design of the original function.
No one has any knowledge/understanding of how the software functions, or displays it's results.

The easiest development language for any project will be UserRPL as it is the most documented and there are multiple users/forums that can provide help.  UserRPL programs will run the slowest

More difficult development language will be SysRPL (or Assembly) since the documentation & actual number of programmers is more limited.  SysRPL programs remove the system checks that are built into UserRPL.  If not designed properly the program may cause random memory deletions, etc.  Also, if changes to the ROM occur, depending on how the program is designed, you may have to make changes to the program before it will operate correctly on the new ROM.

SysRPL programs will run much faster than UserRPL.  The Assembly programs will run faster than UserRPL.

You can also consider programming in C.  There is a set of tools/applications developed that will allow C programming for the 50G.  Other forum members will have to provide further information on how/where to find & implement those tools.  My understanding is that programs written in C run the fastest; however, that will have to be confirmed by someone that has actually used the tools and performance tested the results.

[HP-MACH]

Hi!, zekelegge:

Yes, it's the unique inconvenient, but is very good, alternative.

See ... http://h10010.www1.hp.com/wwpc/pscmisc/vac/us/product_pdfs/HP_StreamSmart_400-lores.pdf