7 votes
Accepted

What would cause a router CPU to run 44x slower?

I can't tell you how to fix the problem, but I think I can explain what is going on. All versions of the TP-Link Archer C9 use a 1GHz processor. You say that there's a 25MHz crystal on it and that it ...
JRE's user avatar
  • 71.4k
6 votes
Accepted

Detect presence of 12MHz squarewave without oscilloscope

With a multimeter measuring voltage: Assuming the esp32 signal source has 50%/50% duty cycle, measure the DC voltage at the output pin...it should be about half of esp32's Vdd. Otherwise, you'll ...
glen_geek's user avatar
  • 25.9k
3 votes

Detect presence of 12MHz squarewave without oscilloscope

I want to detect that the esp32 is outputting the signal out of the intended pin. The following circuit will light up both LEDs if its input has both high and low signals. It can be implemented using ...
Math Keeps Me Busy's user avatar
3 votes

Detect presence of 12MHz squarewave without oscilloscope

Your ESP32 has a "pulse counter" peripheral, which you can program to raise an interrupt every 216 rising input edges. Nice! Route your output pin back to another pin on your ESP32, and ...
Marcus Müller's user avatar
2 votes

Detect presence of 12MHz squarewave without oscilloscope

You can achieve "envelope detection" with a single diode, slightly better with two, plus a small capacitor and a resistor. The diode needs to work at the frequency of interest - "MHz&...
Russell McMahon's user avatar
  • 150k
1 vote
Accepted

Is there any way to get a smaller SPI clock speed specifically to only one SPI slave?

You need to read the AVR data sheet. It explains how to select the SPI clock. If you want you can freely change the clock at any time you want, so if you want different bus clocks for different chips, ...
Justme's user avatar
  • 148k
1 vote

Detect presence of 12MHz squarewave without oscilloscope

You can fashion a logic detect from CMOS gates or such. Bear in mind that you have four things to detect: high-Z (undriven) static low static high changing signal There's plenty of examples of ...
hacktastical's user avatar
  • 54.1k
1 vote

Detect presence of 12MHz squarewave without oscilloscope

Detect presence of 12MHz squarewave without oscilloscope Maybe, if you have a 74AC4040 12-stage binary ripple counter handy, you can reduce the 12 MHz to 2930 Hz. You should then be able to "...
Andy aka's user avatar
  • 457k
1 vote

Replacing clock crystal with signal generator

Your description sounds more like a ceramic resonator, perhaps something like this. Those need to be connected to an oscillator, the resonator itself is just the frequency determining part, so your ...
GodJihyo's user avatar
  • 23.2k

Only top scored, non community-wiki answers of a minimum length are eligible