0
\$\begingroup\$

How does it work?

After research on its pin description in the internet, could not find the exact pins.

  1. What controls the delay time about 2 seconds or about 5 seconds of the outputs between 2 output pins?

  2. What controls the output or routine to repeat itself again when output reached by pin?

When input is supplied either with A3 or A4, the IC outputs 5V from 0V at B1 for about 5 seconds, and again drops to 0V from 5. After a gap of about 2 seconds, another 5V is output at B2 for the same time period, and so on until till B4. As B4 drops to 0V, the output repeat for another cycle starting again from B1 to B4. Then the cycle is complete.

If input is retriggered by A3 or A4, the same routine is executed.

Values of B6 to B9 remains same whether the IC is triggered or just at idle.

enter image description here

enter image description here

\$\endgroup\$

2 Answers 2

Reset to default
1
\$\begingroup\$

The EM78P156 is a microcontroller made by Elan Microelectronics Corporation. From the datasheet I could find, I am not convinced about the reverse-engineered schematic you kindly included (e.g. the blue ceramic oscillator should be connected to the pins you called A3 and A4, really pins 15 & 16, so I doubt those are used as signal inputs; also based on the datasheet, I doubt that 12 V should be applied to any pin e.g. you showed 12 V on pin A2, really pin 17).

However the answers to your questions are quite clear:

  1. What controls the delay time about 2 seconds or about 5 seconds of the outputs between 2 output pins?

The program in the MCU decides this behaviour.

  1. What controls the output or routine to repeat itself again when output reached by pin?

The program in the MCU also decides this behaviour.

\$\endgroup\$
9
  • \$\begingroup\$ Thanks for the inputs...then I'll accept reverse engineering is not possible at all. \$\endgroup\$
    – Thang Tons
    Oct 24, 2020 at 10:35
  • \$\begingroup\$ @ThangTons - Hi, "reverse engineering is not possible at all" Reverse-engineering more of the hardware may be possible (though very difficult for someone to help you with that remotely). Reverse-engineering the MCU firmware may be effectively impossible, if the manufacturer set that "protection bit" to prevent reading of the existing code. Even if they didn't set that protection bit, you would need to get appropriate h/w (likely the MCU programmer) to read-out the code, then reverse-engineer the assembler you would read. Impossible? Perhaps not. Very, very, very, very difficult - yes! \$\endgroup\$
    – SamGibson ♦
    Oct 24, 2020 at 10:41
  • \$\begingroup\$ Also, that aluminium look alike stops the window when it's completely closed. 1. How it is going to sense the status of window by voltage reading or measuring current?? The coil has always 12 v when the module is just standby or when trigger to close windows. 2. How to adjust the sensitivity time of the windows closing? Say, if window closed as soon as it reach the top frame, then power to window motor stops. But, I want to give power still for about 3 seconds say. Please also note that the potentiometer is not responsible for such change in sensitivity. Thanks again. \$\endgroup\$
    – Thang Tons
    Oct 24, 2020 at 10:44
  • \$\begingroup\$ Thanks for all the inputs...then I'll accept reverse engineering is not possible at all. Bdw, actually this module is used in car for auto windows rolling up, and eventually stops when the window is completely closed. It closes one by one all the 4 windows. Also, that aluminium look alike stops the window when it's completely closed. \$\endgroup\$
    – Thang Tons
    Oct 24, 2020 at 10:45
  • \$\begingroup\$ @ThangTons - "1. How it is going to sense the status of window by voltage reading or measuring current??" Likely by another of the ICs (I can't see the other IC numbers clearly) measuring the voltage drop across the current shunt (which I think is what you are calling the "aluminium look alike", W-shaped thick wire, bottom left of the PCB). More h/w reverse-engineering would be needed to confirm. "2. How to adjust the sensitivity time of the windows closing?" Probably by changing the MCU f/w (not realistic), or perhaps by investigating how the current shunt is used (difficult!). \$\endgroup\$
    – SamGibson ♦
    Oct 24, 2020 at 10:55
1
\$\begingroup\$

The EM78P156 appears to be a microprocessor.

The program permanently stored in its read only memory (ROM) controls what it does.

The EM78P156 is not reprogrammable. If you want to change what the board does then you'll have to replace it with a differently programmed controller.

\$\endgroup\$
2
  • \$\begingroup\$ Also, that blue ceramic oscillator has 3 pins.. left has constant 1.6v, middle has 0v constant and right has 2.3 constant... I activated the module by triggering input signal, and the microcontroller activate the relays one after another. Each relay is energized for about 5 seconds. At this time, I placed one terminal of multimeter to the left side pin which always has 1.6 v and other terminal to ground. Surprise thing is that the time period each relay gets energized is increased to 9 seconds ie difference 4 seconds. Why is this so?? \$\endgroup\$
    – Thang Tons
    Oct 24, 2020 at 11:37
  • 1
    \$\begingroup\$ Your multimeter probably messes up the oscillator. It either runs slowly or eratically, or both when you touch it with the multimeter probe. \$\endgroup\$
    – JRE
    Oct 24, 2020 at 12:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.