I used 74HC595(shift register) as a IO expander, and 74AC540P(inverter) to switch the optoisolator. But here is the problem, the shift register can not work correctly. For example, i sent 0x05 to shift reg, the bit 5 and bit 6 is ON.(sent 0x04, bit 4 and bit 5 is ON, and so on.Alike problem)
I connected UNO 5V pin to Vcc, but L led looks dim(Not enough power?). So, i connected UNO Vin pin to Vcc. Also measured 74HC595 & 74AC540P Vcc to gnd voltage is 1.1 Volt, so i think is the problem. How to fixed this problem? Or other bug cause to this problem?
Why the inverters.
The 595 can source and sink, so can drive both opto LEDs.
One resistor/LED between output and ground, and one resistor/LED between output and 5volt.
You might however need separate timings for both (slow, 5ms) optos,
becasuse of possible shoot-through (both being 'on' at the same time).
Wawa:
Why the inverters.
The 595 can source and sink, so can drive both opto LEDs.
One resistor/LED between output and ground, and one resistor/LED between output and 5volt.
You might however need separate timings for both (slow, 5ms) optos,
becasuse of possible shoot-through (both being 'on' at the same time).
What are you switching.
Leo..
Because i want use a bit(an IO) control a pair of opto act like flip-flop(output HV or HV_GND).The circuit took reference from here(support info have circuit diagram). According to above ref, i think the switch time is fast enough to prevent shot-through (not try yet).
pwillard:
You can totally do this without the inverter... by placing the INTERNAL OPTO LEDS in opposite polarities across each other.
Wawa:
Why the inverters.
The 595 can source and sink, so can drive both opto LEDs.
One resistor/LED between output and ground, and one resistor/LED between output and 5volt.
You might however need separate timings for both (slow, 5ms) optos,
becasuse of possible shoot-through (both being 'on' at the same time).
Need to give us a proper Web link