CB3L Wi-Fi Module

by Tuya Inc. - product page

• Info & flashing guide

Information
Board code	cb3l
MCU	Beken BK7231N
Series	BK72XX
Partition layout	Tuya default for N (OTA 0x12A000)
Encryption keys	Beken and Tuya defaults
Specifications
Frequency	120 MHz
Flash size	2 MiB
RAM size	256 KiB
Voltage	3.0V - 3.6V
I/O	12x GPIO, 6x PWM, 2x UART, 1x ADC
Wi-Fi	802.11 b/g/n
Bluetooth	BLE v5.1
FCC ID	2ANDL-CB3L

Usage

Board code: cb3l

In platformio.ini:

[env:cb3l]
platform = libretiny
board = cb3l
framework = arduino

In ESPHome YAML:

bk72xx:
  board: cb3l

Quick flashing guide

• ltchiptool user guide
• full flashing guide

Pin	Connection
P10 / RX1	TX of USB-UART adapter
P11 / TX1	RX of USB-UART adapter
CEN (Chip-Enable)	GND to reset the chip

1. Connect the USB-UART adapter.
2. Start the flashing process.
3. Keep shorting CEN to GND or power-cycling the device, until flashing starts.

Pinout

Pin functions

Name(s)	UART	I²C	SPI	PWM	Other
P0	TX2
P6				PWM0
P7				PWM1
P8				PWM2
P9				PWM3
P10	RX1
P11	TX1
P14
P21
P23, ADC3
P24				PWM4
P26				PWM5

Flash memory map

Flash size: 2 MiB / 2,097,152 B / 0x200000

Hex values are in bytes.

Name	Code	Start	Length	End
Bootloader	bootloader	0x000000	68 KiB / 0x11000	0x011000
App Image	app	0x011000	1.1 MiB / 0x119000	0x12A000
OTA Image	download	0x12A000	664 KiB / 0xA6000	0x1D0000
Calibration	calibration	0x1D0000	4 KiB / 0x1000	0x1D1000
Network Data	net	0x1D1000	4 KiB / 0x1000	0x1D2000
TLV Store	tlv	0x1D2000	4 KiB / 0x1000	0x1D3000
LibreTiny Storage	kvs	0x1D3000	32 KiB / 0x8000	0x1DB000
User Data	userdata	0x1DB000	148 KiB / 0x25000	0x200000
Tuya Storage	tuya	0x1ED000	76 KiB / 0x13000	0x200000

Bootloader and app partitions contain CRC16 sums every 32 bytes. That results in the actual flash offsets/sizes not aligned to sector boundaries. To simplify calculations, the values shown in the table (extracted from bootloader's partition table) were aligned to 4096 bytes.