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Hardware

Michal Zaniewicz edited this page Jun 19, 2026 · 2 revisions

Hardware - Guition JC3636K718C

Source of truth for the pinout: the official manufacturer demo JC3636K718_knob_EN (files pincfg.h + scr_st77916.h). This is the correct pinout for the K/Knob series board - different from the JC3636W518, so don't reuse W518 pins.

Board specs

Part Spec
MCU ESP32-S3 (dual-core, 240 MHz)
RAM 8 MB octal PSRAM, 80 MHz
Flash 16 MB
Display 1.8" round, 360×360
Display driver ST77916 (QSPI), RGB565, inverted colors
Touch CST816 (capacitive, I²C)
Input rotary knob/encoder (rotation only - not pressable)
Audio out PCM5100A external I²S DAC + speaker
Audio in I²S microphone (PDM, 16 kHz)
LED ring WS2812, 13 LEDs, GRB
Storage microSD (SD_MMC)
Power USB-C; some variants add a Li-ion battery + wireless charging
Wireless Wi-Fi 2.4 GHz b/g/n + Bluetooth LE 5.0 (S3 has no Classic/BR-EDR, so no Bluetooth audio); shared 2.4 GHz antenna

Pinout

Display - QSPI (ST77916)

Signal GPIO
SCK (clk) 11
CS 12
D0 13
D1 14
D2 15
D3 16
RST 17
BLK (backlight, PWM) 21

Touch - CST816 (I²C)

Signal GPIO
SDA 9
SCL 10
INT 7
RST 8

Internal SDA/SCL pull-ups are present on the board.

Rotary knob

Signal GPIO
Encoder A 2
Encoder B 1

⚠️ This knob is not a normal A/B quadrature encoder. Direction is encoded by which pin pulses: turning left pulses GPIO2, right pulses GPIO1 (one clean LOW pulse per detent). A PCNT rotary_encoder therefore reads zero. This config uses two independent binary_sensor (inverted + pullup, on_press) instead. The knob cannot be pressed - GPIO0 is BOOT, not a button. Actions are triggered by tapping the screen.

Audio out - PCM5100A DAC (I²S)

Signal GPIO Note
BCK 3
WS / LRCK 45
DO (data) 42
MCK - not used
MUTE 46 LOW = muted → hold HIGH

Microphone - I²S (PDM)

Signal GPIO
SD (data) 4
SCK (clock) 5

LED ring - WS2812

Signal GPIO
Data 0

13 LEDs, GRB order. GPIO0 is also the BOOT/strapping pin - it works fine as a WS2812 output after boot; ESPHome may print a strapping-pin warning (harmless here).

Battery - ADC

Signal GPIO
BAT_ADC 6

~10k/10k divider → multiply by 2. See the battery notes in Troubleshooting - the percentage is approximate.

microSD / TF (SD_MMC)

Signal GPIO
CLK 39
CMD 38
D0 40
D1 41
D2 48
D3 47

(Not used by this config, listed for completeness.)

Buying one (AliExpress)

Search for the exact model number and verify the listing matches:

  • Model: Guition JC3636K718 (look for this in the title/photos)
  • ESP32-S3, 16 MB flash, octal PSRAM
  • 1.8" round 360×360, driver ST77916
  • touch CST816, rotary knob, speaker + mic, LED ring

⚠️ Heads-up: there's a near-identical board, the JC3636W518, with a different pinout. Make sure the listing says K718, not W518.

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