Click Here to see the project from the beginning
I found another TFT touchscreen in my ‘archive’ of parts, so I took the opportunity to switch gears for a while and work on the firmware system. I’ll probably do that for a couple more days, then back to hardware.
The tuning knob in this system is implemented with a rotary encoder that has a push-button switch in the shaft. The tuning resolution can be set anywhere from single Hz per encoder step to single Mhz per encoder step. Pushing the knob in while turning it moves an underline cursor to show which digit is being controlled. Pushing the button and holding it without turning for about 2 seconds saves the whole radio state to EEPROM so the radio always powers up in the state you left it in. Pushing the knob and holding it for about 5 seconds clears all the digits lower than the cursor position to zeros. This is all working now. Another encoder will be added to control the volume of an audio power amp with voltage-controlled-gain via a DAC. This will be the underpinning of my intended software defined feed-forward audio AGC.
Touching any of the on-screen soft-buttons toggles to the next control state state of that button. Touching the orange “Menu” button redefines all the buttons with a different set of control functions.
The S-Meter is a moving bar that will be calibrated in accurate S units.
All the firmware infrastructure for these features is in place, waiting for hardware to control.
Back to that soon.
W3JDR Bright Ideas 
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