Frequency Counter 2Hz ... >60MHz Using The ATtiny424's "EVENT" System
This Frequency Counter is using the ATtiny424 micro-controller. Via its "EVENT" System and the RTC Interval Timer its hardware for the sequence control is inside the mc. Reciprocal frequency measurement, displaying 7/8 digits, is in use. The TCXO TG2520SMN 20MHz supplies the reference clock.
Frequency Counter 2Hz ... >60MHz Using The ATtiny424's "EVENT" System
* Sequence control via the ATtiny424's "EVENT" system and RTC Interval Timer.
This means, that timers TCB0 and TCB1 are configured in CAPTURE mode via PINA1
as a 32-bit reference counter and TCA0, also via PINA1, as a 16-bit measurement counter.
* Reference clock via the inexpensive TCXO TG2520SMN 20MHz, temperature coefficient < 5*10^-7,
frequency deviation can be adjusted in the software (F_CPU in 'lcd_drv.h'). The TCXOs I
owned, have a deviation of < 5*10^-8 (measured with a GPS-guided counter)!
* The firmware was created with Microchip Studio 7. The memory usage is approximately 80%.
* Reciprocal frequency measurement. Displaying 7/8 digits (f > 10Hz).
* Power supply 5V DC, preferably via USB. The "power bank keeping alive" can be switched off.
Reverse polarity protection exists.
* The power voltage is displayed (resolution 5mV)
Scaling can be adjusted in 'main.c' <#define U_K 32233UL>
* The potentiometer controls: Switching between frequency display and period display
Gate time: 1 to 9 s
Switching off the "power bank keeping alive"
* Sensitivity is <15mV RMS 5Hz to 10MHz, <50mV RMS <60MHz.
* PCB software: Target V33make.
* PCB was created using toner transfer, therefore only center holes are present.
* Mostly components of my stock were used, which can often be replaced with similar parts.
* Sequence control via the ATtiny424's "EVENT" system and RTC Interval Timer.
This means, that timers TCB0 and TCB1 are configured in CAPTURE mode via PINA1
as a 32-bit reference counter and TCA0, also via PINA1, as a 16-bit measurement counter.
* Reference clock via the inexpensive TCXO TG2520SMN 20MHz, temperature coefficient < 5*10^-7,
frequency deviation can be adjusted in the software (F_CPU in 'lcd_drv.h'). The TCXOs I
owned, have a deviation of < 5*10^-8 (measured with a GPS-guided counter)!
* The firmware was created with Microchip Studio 7. The memory usage is approximately 80%.
* Reciprocal frequency measurement. Displaying 7/8 digits (f > 10Hz).
* Power supply 5V DC, preferably via USB. The "power bank keeping alive" can be switched off.
Reverse polarity protection exists.
* The power voltage is displayed (resolution 5mV)
Scaling can be adjusted in 'main.c' <#define U_K 32233UL>
* The potentiometer controls: Switching between frequency display and period display
Gate time: 1 to 9 s
Switching off the "power bank keeping alive"
* Sensitivity is <15mV RMS 5Hz to 10MHz, <50mV RMS <60MHz.
* PCB software: Target V33make.
* PCB was created using toner transfer, therefore only center holes are present.
* Mostly components of my stock were used, which can often be replaced with similar parts.
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