FT817 external display architecture

ATtiny or ATmega for the External Display? This is the question!

After I have fought with the tiny2313 to fit all requested features for the external display (for transverters), and lost ... after I have searched up and down the Net for the ATtiny4313 PDIP and realized that it is probably not yet in production ... I gave up.

The choice was whether to maintain backward compatibility with the stand-alone keypad based on ATtiny2313 OR establish a new standard, compatible with the "remote control" to-be.

While the ATmega chip can cost 3 times the ATtiny uC, it gives me much more freedom to produce something not only satisfactory, but fitting all the requirements. And leaves headroom for future extensions. Moreover a PCB drawn and produced for the display can be done for the keypad+display at the same time, just leave out components when assemblying.

So, ATmega48/88/168 is the final choice. Probably an ATmega48 will suffice.

In any case I will not throw away the ATtiny2313 external display firmware for those who have built the circuit published in the last month (October 2010). It will be available on request.


In any case the 2*16 LCD display based on HD44780 controller will not change.

Survey on your microwave equipment

The interaction with an active microwaver has been very instructive and helpful for the development of my external display firmware. But I would like to hear also other opinions.

I have arranged an online survey in three questions. It's anonymous but will help me gather a broader overview on the microwave "land".

Please spend two minutes with my survey. I can leave it running for 10 days, so until October 31st, 2010.

I will publish aggregate results here once the survey is over.

Thank You!

Short-term projects, end of 2010

For the short-term period, let's say end of 2010, I have the following shack-wishes to achieve:

• Design and test an ATmegaNM stand-alone fuse restorer
• Design and build an HF/4m transverter (TX-only)
• Assemble a keypad+display prototype on perfboard

I think I had planned something more, but I don't remember it :-)

External display for transverter use - one more update

One more update to the firmware and diagram of the external display for transverters. Since there was a little bit of program space left, I added the support for a VFO A/B swap button.

Now you need two N.O. pushbuttons and one DPST switch.

If you don't want the A/B function, leave out the pushbutton but do insert the 10k pull-up resistor. Same for the dual LO, just put a pull-up resistor between pin 12 and 5Vcc if you won't be using a transverter with input into the UHF region.

FT817 external display for transverter, updated

101010: I have managed to "sign" this date with a new (internal) firmware version for the external display for transverter users.

The new firmware allows L.O. values for 10 GHz (and more) transverters. The programming occurs as announced before, reading the display frequency and interpreting it as GHz instead of MHz.

But two L.O. frequencies can be stored, one to be used when the 817 (857, 897) is tuned to HF/VHF and another for UHF. According to a microwave experimenter, with this option it is possible to use 10 and 24 GHz transverters. UHF is recognized automatically by the display, and L.O. value varied accordingly.

Since automatic band recognition is enabled, there is also an output pin switching high from HF/VHF to UHF in order to switch transverters! One radio, one external display, two transverters! All within an ATtiny2313.

Here is a preview on the schematic diagram. Firmware will be published on the usual website. But it's available on request since now.


PS: this firmware works on FT817, FT857 and FT897, and their ND versions.

FT817 remote, on the way... (2)

A short update on the remote control project.

A preliminary version of the circuit layout is working on breadboard. It includes an ATmega168, a PCF8574A TWI I/O expander, matrix keypad and LCD display.

I have been able to read the keypad using interrupts and display keypress on the LCD. I have been able, with another piece of firmware, to read data from the FT817 and display it on the LCD.

Now it is "just" matter of putting both codes together and working on a firmware logic that combines a continuous frequency display, keypad input and a sort-of menu driven function selection.

5W LED vs. halogen spotlights

I wanted to compare a power LED with something "similar", like a spotlight. The sink of my kitchen, sitting in a dark corner, was found to be an optimal location. Moreover the cooking area has two 20W halogen spotlights. Since they are next to each other, what a chance to compare them directly!

I took a wall-wart power supply, said to output 9Vdc, 1A max. I measured it under load to be at 10.3Vdc. So with my surplus power resistors summing up to 12.7 ohm, I could drive the LED at about (10.3-5.9)/12.7 = 0.34A (measured 0.32A).

The result is shown in a short youtube video, composed of few pictures.

As a practical result, the sink area is very well lit even at just 2W input. The cold white light gives an unreal look to the inox sink, but colors are not distorted.

The heatsink has been equipped with two thin magnetic strips (superglued), so that the installation is not permanent.

FT817 keypad has new website

I have spent a little time restyling the corner of my website dedicated to the external keypad for FT-817 (FT-857, FT-897). I hope the new look delivers all information in an easier way.