I don't get any reaction on the knock-indicaton. It shows max all the time unless you disables it, then it shows "1" and it may vary between 0 and 2.
Q: Is a certain firmware recommended when useing knock-sensor?
- no change in knock code for looong
Q: Does any one got knock-sensor/indicator working?
- who? config?
I'm setting op the knock-sensor but I only got a 16MHz crystal with the board, and I see 4MHz is the normal setup.
- I'll be ordering some boards in a few days anyway.. I'll just ad a note about a extra 4MHz crystal.
- have you mounted the 4 MHz crystal? Yes
Q The "knock-chip" has a programmable-divider so it can also use a 16MHz crystal if it is set up, but where to set up/program this divider?
A: You need to recompile firmware with the following line added to my_make: "MY_CONF += -D KNOCK_OSC=16", then the knock chip is initalized with the correct divider for the 16MHz crystal.
Knock-frequency around 7kHz.. from about 6,2-7,8KHz.
Engine: VW 1800 8v. 81mm bore, 86,4mm stroke.
Publish the wav file of the knock sensor recorded with your notebook when you cling the block with a wrench. (so we can verify freq, although 7kHz "sounds" reasonable)
onboard knock setup
I have connected the shield to GND outside the box, and connected the two wires to "knock 1" ("ch. 0" in MegaTune).
- See knock_conf below to verify channel selection
knock_conf=FD #0xFF=Enable knock detection and ignition retard. # MegaTune changes it to: FC (disable)
- from global.h: uint8_t knock_conf; // knock, config. bit0 1:enable bit1: 0:channel0 so =>
- FF means knock2...
- FD means knock1... (DEFAULT!)
knock_sampling_window=e2 # any good suggestions?
knock1_frequency=29 # decimal 41 6.94kHz
knock1_gain=14 # How much gain is estimated to bee needed?
knock1_integrator=11 #any good suggestions?
knock_threshold=50 # Threshold to determine if retard needed
knock_noise_scale=10 # any good suggestions?
knock_max_retard=18 #6 degrees
knock_default_retard=08 #2 degress
knock_retard_step=04 #1 degree
For the gain and knock_threshold (the ratio of these is what mostly counts), much depends on your sensor, engine. Even screw fastening torque changes amplitude somewhat.