Beken BK7256 320 MHz dual-core RISC-V IoT MCU offers WiFi 6, Bluetooth 5.2, JPEG video encoder/decoder

Until now, I had only heard about Beken Bluetooth audio chips, but I’ve just been informed the company is also making WiFi chips such as the BK7256 that are notably found in some Tuya Smart Home modules.

Beken offers both RISC-V and Arm WiFi and Bluetooth chips with features summarized as follows:

BK7235 single-core RISC-V MCU up to 320 MHz with 2.4 GHz WiFi 6 802.11ax and Bluetooth 5.2 LE, 4MB flash, 512KB SRAM, optional 4MB PSRAM
BK7236 dual-core Arm MCU up to 120 to 240 MHh with 2.4 GHz WiFi 6 802.11ax and Bluetooth 5.3 dual mode, 4MB flash, 512KB SRAM, optional 4MB PSRAM
BK7237 dual-core RISC-V MCU up to 320 MHz with 2.4 GHz WiFi 6 802.11ax and Bluetooth 5.2 dual mode, 4 or 8MB flash, 512KB SRAM, optional 4MB PSRAM
BK7256 dual-core RISC-V MCU up to 320 MHz with 2.4 GHz WiFi 6 802.11ax and Bluetooth 5.2 dual mode, 4MB flash, 512KB SRAM, 8MB PSRAM, JPEG encoder

Let’s look into the KB7256 specifically, and see what software support and development kits are available for the Beken WiFi chips.

Beken BK7256 specifications:

CPU – Dual-core 32-bit RISC-V MCU at up to 320 MHz with FPU, MPU, 32KB I/D TCM, 64 I-cache, and 16KB D-cache per core; EEMBC CoreMark score: 1 core at 320 MHz: 3.57 CoreMark/MHz
System Memory – 512 KB shared SRAM, 8 MB SiP PSRAM
Storage – 4 MB SiP flash, 64 KB ROM, 32 bytes eFuse, 8 Kbit OTP
Video – JPEG hardware encoder/decoder
Wi-Fi
- IEEE 802.11b/g/n/ax 1×1 compliant
- 20/40 MHz channel bandwidth for 2.4 GHz
- DL MU-MIMO and UL OFDMA support
- Individual Target Wake Time (iTWT)
- TX and RX low-density parity check (LDPC) support for extended range
- WPA/WPA2/WPA3-Personal support security
- Working mode: STA, AP, Direct, concurrent AP + STA
- Integrated BT/WLAN coexistence (PTA)
- TX power up to +18 dBm
- RX sensitivity -99 dBm
Bluetooth
- Dual-mode Bluetooth 5.2 compliant
- Supports Basic Rate (BR), Enhanced Data Rate (EDR) 2 Mbps and 3 Mbps, Low Energy (LE) 1 Mbps, 2 Mbps, and long range (125 kbps and 500 kbps)
- Advertising extensions
- Bluetooth direction finding: Angle of Arrival (AoA) and Angle of Departure (AoD), plus antenna array with up to sixteen antennas for precise indoor positioning
Peripherals
- 1x SD/SDIO
- Display – LCD interface (16-bit parallel RGB and I8080)
- Camera – 8-bit CIS DVP camera interface
- Audio – 1x I2S, 1x audio ADC, 1x audio DAC, four-band digital hardware equalizer, SBC decoder accelerator, microphone input amplifier, speakers amplifier
- USB – 1x full-speed USB OTG (FS)
- Up to 48 GPIOs
- 2x SPI, 1x QSPI, 2x I2C
- 3x UART: 1 with hardware flow control, 1 with flash download support
- 1x CAN controller with CAN FD
- Up to 12x 32-bit PWM
- Up to 8-channel 13-bit SAR ADC
- Up to 16x touch sensors
- 1x temperature sensor
- 1x IrDA
- DMA – 1xgeneral-purpose DMA controller (GDMA) with 6 channels, 1x DMA2D controller
- Timers
  - 6x 32-bit general-purpose timer/counter
  - 2x watchdog timer
  - 1x real-time counter (RTC)
Security
- Isolated secure element and hardware cryptography
- Secure boot
- Unique ID and secure storage
- Secure update and anti-rollback
- Lifecycle management such as secure debug
- Flash encryption
- Cryptographic hardware acceleration
  - Crypto accelerator: DES, AES-128/192/256, ChaCha20-128/256, SM4-128
  - Public key accelerator: ECDSA-P256/P384, RSA-2048/3072, SM2
  - Hash: SHA-224/256, SHA-384/512, HMAC, Poly1305, SM3-512
  - True Random Number Generator (TRNG)
Clock Management
- External oscillator: 26 MHz crystal oscillator (X26M), 32.768 kHz crystal oscillator (X32K)
- Internal oscillator: 32 kHz ring oscillator (ROSC), 26 ~ 240 MHz digitally controlled oscillator (DCO)
- 320/480MHz PLL (DPLL)
- Audio PLL (APLL)
Power Management
- 2.7 to 5.0 V VBAT supply
- On-chip power-on reset (POR) and brown-out detector (BOD)
- Embedded buck (DC-DC) converter and LDO regulators
Power consumption:
- Active mode RX: 63 mA
- Active mode TX: 250 mA
- Low voltage standby mode: 150 μA
- Deep sleep mode: 15 μA
- Shutdown mode: 2.0 μA
Package – 8x8mm QFN68 package
Temperature Range – -40°C to +125°C

Beken BK7256 development board — BK7256 development board

Beken provides development boards for each of their BK72XX microcontrollers and fairly detailed documentation in Chinese and English (some sections are not translated yet) where you’ll find the datasheets for the chip, instructions to get started, an API reference, and sample code for video, audio, Bluetooth, a doorbell, and command line usage. All new Beken chips (BK7235, BK7236, BK7237, BK7256) are supported by the Armino development framework hosted on GitHub. The framework currently works for FreeRTOS and LiteOS, and the company is also working on getting it ported to RT-Thread and AliOS.

Applications for the BK7256 include smart speakers, low power cameras, motor control, and Smart Home appliances. The chip is also found in one upcoming “Wi-Fi and Bluetooth Low Energy Combo Core Board” from Tuya. I could not find any BK7256 boards or modules on Aliexpress, and the official board might need to be sourced directly from Beken at this time.

Thanks to Rogan for the tip.

Jean-Luc Aufranc (CNXSoft)

Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011.