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For more beautiful JUMA(LCD display unit)

PostPosted: 14 Feb 2015 02:26
by JH1GVY
I deleted the contribution.
JH1GVY Mori

Re: For more beautiful JUMA(LCD display unit)

PostPosted: 14 Feb 2015 06:46
by 5B4AIY
As you say, a much better display. They should also enhance the Juma TRX-2 and PA-100D. However, where can we purchase these? I would then consider replacing them in my TRX-2/PA-100D, and would also ensure that that firmware was compatible.
73, Adrian, 5B4AIY

Re: For more beautiful JUMA(LCD display unit)

PostPosted: 14 Feb 2015 09:47
by JH1GVY
I apologize for having confounded you.
I understand that it is difficult to change a kit.
The purpose of this report takes that the individual who purchased a kit
remodels it by oneself into consideration.

JH1GVY Mori

Re: For more beautiful JUMA(LCD display unit)

PostPosted: 16 Feb 2015 09:01
by SM0KMX
What type of display are you talking about

sm0kmx Lennart

Re: For more beautiful JUMA(LCD display unit)

PostPosted: 17 Feb 2015 15:08
by 5B4AIY
To answer your question, these displays are the newer Organic LED displays that offer a higher contrast and brighter display compared to the usual LCD variety.

They are available in a number of different formats from a variety of manufacturers, but those of particular interest are the ones that are mechanically and electrically compatible with the popular LCD variety. Typically, these are the 1602A derivatives that offer two lines of 16 characters, as well as the 1601A variety offering a single 16-character line display.

Most of the LCD displays use the well-known Hitachi HD44780 controller's command set, and for compatibility, these newer OLED displays utilise a similar command set or an emulation. This should ensure full firmware compatibility, although the word 'should' needs to be noted. Even among the existing LCD displays there exists a wide variety of timing differences, and this can be crucial to the overall satisfactory functioning of any retrofitted replacement display.

In my Juma TRX-2 and PA-100D firmware I have tried to adopt the most conservative approach to display timing and have allowed for the worst-case specifications I could find, thus if you ever have to replace a display then in all probability your replacement will work just fine with my firmware.

The only somewhat 'touchy' issues relate to the built-in character set and the custom character emulation. The only ROM characters other than the ASCII characters that are used are the VFO Lock symbol for the Juma TRX-2 and the temperature degree symbol for the PA-100D. If any discrepancies were to be discovered it would be a simple firmware 'fix' to overcome.

The custom character set however is used extensively in both the Juma TRX-2 and the PA-100D for the graphic meter scale, and any discrepancies in this area would be hard to correct. I am tempted to go ahead and try one of these OLED displays and verify its timing and character sets, but as there are a number of different manufacturers it would be an expensive business to check them all, and the technical documentation is somewhat lacking. (at present)

In the Serial Test Suite in my firmware for both the Juma TRX-2 and the PA-100D there is a display test feature that exercises the display with all 256 possible character codes as well as the custom characters and displays the result, thus if you do think you have a problem, then this test can be invoked to verify compatibility or for other diagnostic purposes, for example, defective display pixels, or stuck interface bits.

73, Adrian, 5B4AIY