FT6336 Datasheet Notes: I2C Address, Registers & Touch Fixes

Manufacturer	FocalTech
Type	Touch controller
Interfaces	I2C
Max resolution	2 touch points

FT6336 at a glance

Item	Value	Source
Touch points	2, or 1 plus gestures	FT6336G datasheet
I2C address (7-bit)	`0x38`	Adafruit and Espressif drivers
I2C SCL	10 to 400 kHz	FT6336G datasheet
Report rate	Up to 100 Hz	FT6336G datasheet
Operating voltage	2.8 V to 3.6 V	FT6336G datasheet
IOVCC	Independent, 1.8 V to 3.6 V	FT6336G datasheet
Operating temperature	−40 °C to 85 °C	FT6336G datasheet

The datasheet's features list gives 2.8 V to 3.6 V, while its DC table lists VDDA and VDD3 as 2.8 V to 3.3 V. Design for the narrower range unless your module supplier says otherwise.

Which FT6336 do you have?

Part	Channels	Package	Panel size
FT6336G	31	QFN 5×5, 40 pins	Up to 4.0″
FT6336DMB	36	QFN 6×6, 48 pins	Up to 4.5″

These figures come from two FocalTech datasheets: the FT6336G v1.0 and the FT6X36 series v0.3. We did not find a datasheet for the FT6336U, so what we say about it comes from driver source code.

Reading a touch

ESPHome's FT63x6 source reads these registers:

Register	Contents
`0x00`	Device mode (ESPHome writes `0x00`)
`0x02`	Number of touches, low 4 bits
`0x03`	Event in bits 7:6, X high bits in bits 3:0
`0x04`	X low byte
`0x05`	Touch ID in bits 7:4, Y high bits in bits 3:0
`0x06`	Y low byte
`0x07`	Touch weight
`0x80`	Touch threshold
`0x88`	Active touch rate (ESPHome writes `0x0E`)
`0xA3`	Chip ID

The second touch uses the same layout 6 bytes higher, starting at 0x09. ESPHome ignores a touch count of 0x00 or 0xFF.

Reset and power-on timing

From the FT6336G datasheet:

Reset pulse (Trst): at least 5 ms low on RSTN.
After reset (Trsi): at least 300 ms until it starts reporting points.
After power-on (Tpon): at least 300 ms until it starts reporting points.
Before power-on: hold RSTN low. INT and the I2C lines are also advised to be low.
Power cycling: let the supply fall below 0.3 V for more than 5 ms.

Drivers differ here. Linux's edt-ft5x06 driver waits 300 ms after releasing reset, which matches the datasheet. ESPHome's reset routine holds reset low for 10 ms and adds no wait after releasing it. Espressif's FT5x06 driver holds reset for 10 ms, then waits 10 ms.

Operating modes and I2C

The datasheet lists three modes:

Active: scans at a default 60 frames per second, and the host can change this.
Monitor: scans at a default 25 frames per second. A touch returns it to Active. The datasheet says "the serial port is closed" in this mode.
Hibernation: power-down mode that needs a reset or wake-up signal from the host.

The Monitor mode note can matter for I2C scans on an idle panel. We have not measured this ourselves, so treat it as something to rule out: touch the panel while you scan.

Symptoms and fixes

Symptom	Check
Nothing at `0x38`	Confirm RSTN is high, wait 300 ms after reset, then touch the panel while you scan. Then check SDA, SCL and pull-ups.
ESPHome logs "FT6336U touch driver failed to start"	ESPHome read `0` from `0xA3`. It logs this and continues, so check wiring and reset timing.
Library rejects the chip ID	IDs differ by part: Adafruit lists `0x06` FT6206, `0x36` FT6236 and `0x64` FT6236U and FT6336U. Check which values your library accepts.
Touch too sensitive or not sensitive enough	Register `0x80` is panel-dependent. Adafruit defaults to 128, "calibrated" for its own 2.8″ screen, and Espressif's FT5x06 driver writes 70. Don't assume either suits your panel.
A third finger is not reported	This is the chip's limit: the datasheet and the Linux driver both give 2 points. For more points, see GT911.

Driver support

ESPHome: use the ft63x6 platform with optional reset_pin and interrupt_pin. I2C must be configured. Its docs name the WT32-SC01 board, and its source logs FT6336U.
Linux: there is no FT6336 entry. The closest is focaltech,ft6236 in the edt-ft5x06 driver, with 2 points and required compatible, reg and interrupts properties. We have not tested this with an FT6336.
ESP-IDF: the esp_lcd_touch_ft5x06 driver uses address 0x38 and 100 kHz by default. Its source covers up to 5 points and does not name the FT6336, so check your part before you rely on it.
Arduino: Adafruit's FT6206 library defines FT6336U's chip ID and defaults to 0x38.

Related controllers

For one-finger touch on round displays, see CST816S. For larger panels, see GT911. The M5Stack Core2 is one board that uses an FT6336U.

Guides & comparisons

Guide

How to Choose a Display for ESP32-S3 (SPI, QSPI, RGB)

Pick the interface and resolution from two numbers: how many bits per second the bus can move and how much memory the frame needs. With worked figures and reference builds.

FT6336 troubleshooting & FAQ

What is the FT6336 I2C address?

Adafruit and Espressif drivers use 0x38 (7-bit), and Linux uses the same value in its FT5x06-family binding example. The FT6336G datasheet we read does not state the address, so confirm it with an I2C scan on your board.

Why does my FT6336 not respond on I2C?

Check that RSTN is high, then wait at least 300 ms after reset: that is the datasheet minimum before it reports points. The datasheet also says the serial port is closed in Monitor mode, so touch the panel and scan again before you suspect the wiring.

What is the difference between FT6336, FT6336G and FT6336U?

FocalTech’s datasheets list the FT6336G with 31 channels for panels up to 4.0″, and the FT6336DMB with 36 channels for panels up to 4.5″. We did not find a datasheet for the FT6336U. Adafruit’s library gives it chip ID 0x64, the same as the FT6236U.

FT6336: datasheet notes & setup