Feature Request: Support FTC532 Touch Controller

[vic42]

PROBLEM DESCRIPTION

A clear and concise description of what the problem is.
Chinese touch switches utilizing the FTC532 touch chip are not supported

REQUESTED INFORMATION

Make sure your have performed every step and checked the applicable boxes before submitting your issue. Thank you!

• Read the Contributing Guide and Policy and the Code of Conduct
• Searched the problem in issues
• Searched the problem in discussions
• Searched the problem in the docs
• Searched the problem in the chat
• Device used (e.g., Sonoff Basic): Teekar Smart Curtain Switch
• Tasmota binary firmware version number used: 9.1.0.2
  • Pre-compiled
  • Self-compiled
• Flashing tools used: _____
• Provide the output of command: Backlog Template; Module; GPIO 255:

  Configuration output here:

N/A

• If using rules, provide the output of this command: Backlog Rule1; Rule2; Rule3:

  Rules output here:

N/A

• Provide the output of this command: Status 0:

  STATUS 0 output here:

N/A

• Set weblog to 4 and then, when you experience your issue, provide the output of the Console log:

  Console output here:

N/A

TO REPRODUCE

Steps to reproduce the behavior:
Flash the switch with Tasmota

EXPECTED BEHAVIOUR

A clear and concise description of what you expected to happen.

The three touch buttons should be detectable as switch inputs to Tasmota

SCREENSHOTS

If applicable, add screenshots to help explain your problem.

LA traces drom top to bottom:

1. no key pressed
2. left key pressed
3. middle key pressed
4. right key pressed
5. all three keys pressed

ADDITIONAL CONTEXT

Add any other context about the problem here.

There is just one line (Pin4 of 8) of the FTC532 chip connected to the ESP module through GPIO14. I analyzed the transmission protocol. The FTC532 is constantly sending the touch pads' status.

I assume the protocol is capable of reporting 2 groups of 4 touch sensors each.
Here is my protocol decode:

Frame Period: 21.85 ms (58 cycles)
Bit Period: 377 µs

IDLE  = 3015 µs
LEAD  =  755 µs
SHORT =  377 µs
LONG  = 1130 µs

T = 377 µs

IDLE  = 8T HIGH
LEAD  = 2T LOW, 1T HIGH
SHORT = 1T LOW, 1T HIGH
LONG  = 3T LOW, 1T HIGH

LEAD-IN = 3015 µs HIGH, 755 µs LOW

S = 377 µs HIGH,  377 µs LOW
L = 377 µs HIGH, 1130 µs LOW

          GROUP1   GROUP2
---------------------------
ALL OFF: SSSSLLLL SSSSLLLL
 1 ON  : LSSSSLLL SSSSLLLL
 2 ON  : SLSSLSLL SSSSLLLL
 3 ON  : SSLSLLSL SSSSLLLL
 4 ON  : SSSLLLLS SSSSLLLL
 5 ON  : SSSSLLLL LSSSSLLL
 6 ON  : SSSSLLLL SLSSLSLL
 7 ON  : SSSSLLLL SSLSLLSL
 8 ON  : SSSSLLLL SSSLLLLS
 
 
1-3 ON : LLLSSSSL SSSSLLLL
ALL ON : LLLLSSSS LLLLSSSS

Example timing ALL OFF frame in clock cycles T=377µs, triggering on rising edge:
IDLE-22222444422224444-IDLE

I know programming, yet I'm looking for engagement of Devs more experienced with the Tasmota code.
Opened this issue on behalf of the original requestant to keep it on the "radar".
(Please, remember to close the issue when the problem has been addressed)

[snookyly]

As the original requestant I would like to thank @vic42 for his great analysis. The FTC532 touch controller is assembled to the 4th gen Teekar curtain switch (https://www.amazon.de/dp/B07XJWYZR4) and the Teekar 2-gang wall switch (https://www.amazon.de/dp/B07SLJ8JYJ). I'd would be great if both devices get the tasmota support.

[vic42]

I made some progress in creating a driver.

It appears a bit slow in the log but that may be a logging issue.

[vic42]

Driver programming finished.
The driver is in final testing and proof-reading stage now.
There will be a PR for it soon.

[vic42]

Driver has been merged into Tasmota Development branch.
#define USE_FTC532 to include it in your build.

[snookyly]

Successfully tested. Thanks for implementing.
Can be closed.