cannot find tri state buffer in logicworks

The output enables are controlled by the Arduino: When the Arduino decides which channel has the highest frequency for a given axle, it enables the output corresponding to that channel's input, effectively tying that speed sensor input to the ECU through the buffer.

My inclination would be to have the signals run to 4 tri-state buffers (like a single CD74HCT126 IC) pairs of outputs are wired together. TBH, I don't think I would try to have the Arduino replicate the waveform though it might be reasonably possible via output compare operations. Given the hardware connection limits of timer hardware solutions, this might be the best route but you'd need to characterize it. At 120MPH, a 48-tooth sensor would produce a 1.3kHz pulse stream which has a period of ~730uS so you'd be doing RISING or FALLING edge interrupts on 4 pins, each of which is going to be giving an active pulse every 730uS. I don't know the number of pulses per revolution of your wheel sensors but I've seen tooth counts of 39 and 48 teeth as examples. You might be able to pin change interrupts on the Mega (available on pins 2, 3, 18, 19, 20 & 21.) The feasibility of this approach needs further consideration. You could, in theory, use the wheel sensor inputs as clocks to each of the 4 16-bit timers via T1,3,4 & 5.) Unfortunately, the Mega2560 design neglects to bring T1, 3 and 4 to connectors (T5 is available at pin 47.) Unfortunately, the way the Mega2560 board is wired the input capture pins for timer 1 and 3 are not brought out to connectors (ICP4 is on pin 49 and ICP5 is on pin 48.)

You could, in theory, connect the inputs from each wheel sensor to its own input capture pin (ICP1,3,4 & 5). So instead to use just one sensor for one front wheel and rear wheel, i'd like to have sensor on all wheels and calculate the faster wheel in front and rear axle.Ī Mega has 4 16-bit timers (Timer1, 3, 4 and 5). I just want to transform 4 signals into 2 output signals to use less ECU inputs. So 2 differents signals to represent front and rear wheel speedįor ECU that is already a common usage having this rotation signal. To make it clear I will have this differential calculation for front wheels and also for rear wheels. This calc makes possible to have just one signal representing the velocity even in a curve or straight line Usually, the guys use one sensor for one front wheel (left or right) and another for the rear wheel (left or right), however, the wheel speed is different for the left or right wheel into a curve, for this reason I'm intending to use a differential calculation to take the faster wheel. Summarizing the ECU uses this signal for traction control to know if there is a disruption of the traction wheel in relation to the reference wheel, to apply the appropriate correction. What's the maximum expected frequency of the wheel speed sensors? For what does the ECU use the fastest wheel speed sensor signal?Īssuming the logic works well, there may be discontinuities when the fastest wheel changes will that potential hiccup in the output signal cause the ECU any problems?

Cannot find tri state buffer in logicworks