Hisilicon Hi3861 may be the first RISC-V WIFI SoC we’ve reported on, but due to political uncertainties and security concerns, supplies may not be available outside of China.
So alternatives are welcomed, and Nanjing-based Bouffalo Lab (not a typo, 博流智能科技 in Chinese) has recently introduced BL602 and BL604 32-bit RISC-V WiFi and Bluetooth LE SoC for low-power IoT applications that are supposed to compete against ESP8266 in terms of price but with higher performance and additional features. The BL602 will also be integrated into an upcoming Sipeed Longan-series board, and potentially a new IoT board from Pine64.
- MCU subsystem – 32-bit RISC-V CPU with FPU with dynamic frequency from 1MHz to 192MHz, L1 cache
- Memory – 276KB SRAM on-chip
- 128KB ROM, 1Kb eFuse, and optional Embedded Flash on-chip
- XIP QSPI flash support
- Wi-Fi 4 – 802.11 b/g/n @ 2.4 GHz
- Bluetooth 5.0 LE
- Wi-Fi Fast connection with BLE assistance
- Wi-Fi Security – WPS/WEP/WPA/WPA2/WPA3
- STA, SoftAP, and “sniffer” modes
- Integrated RF balun, PA/LNA
- WiFi Tx: 21 dBm; WiFi Rx: -98 dBm
- Peripherals and I/Os
- SDIO 2.0 slave (AP-Host)
- SPI master/slave, 2x UART, I2C master/slave, 5x PWM channels
- ADC – 10-bit general DAC, 12-bit general ADC, 2x general analog comparators
- PIR (Passive Infra-Red) detection
- IR remote HW accelerator
- 16x flexible GPIOs (BL602) / 23x flexible GPIOs (BL604)
- 4x DMA channels
- RTC timer up to One year
- 2x 32-bit general-purpose timers
- Clocks – Supports XTAL 24/26/32/38.4/40MHz, XTAL 32/32.768KHz, internal RC 32KHz & 32MHz oscillator, internal system PLL
- Secure boot
- Secure debug
- XIP QSPI On-The-Fly AES Decryption (OTFAD)
- TRNG (True Random Number Generator)
- PKA (Public Key Accelerator)
- Debugging – JTAG
- Supply Voltage – 2.1 to 3.6V
- Low power modes – Off, hibernate, power down sleep, and active
- Power consumption – Deep sleep: 0.5uA; WiFi Rx: 18 mA
- Package Type – 32-pin QFN (BL602) or 40 pin QFN (BL604)
- Temperature range – -40°C to 125°C
The specs are made of the information there is on Bouffalo website, plus extra information I found on the Internet. I first found about BL602 thanks to a Tweet by Sipeed.
Longan series (RISC-V) will add new boards:
1. RV32 WIFI+BT Soc up to 200MHz
2. ~300KB SRAM + 2MB in chip flash
3. as cheap as esp8266
what software env you want for this platform? mpy? rust?
what about PlatformIO support?
— Sipeed (@SipeedIO) October 22, 2020
Somehow there seems to be a lot of people asking for Rust support, a high-level programming level that can also be used for embedded devices. But we may also get Arduino/PlatformIO and MicroPython support. Anyway, that’s the tweet where I learned about BL602 and that it would be as cheap as ESP8266. TL Lim, the founder of Pine64, also participated in the discussion and would consider launching a Pine64 BL602 board if an open-source toolchain is available.
The information we have so far is interesting, but it gets even better when we look at Bouffalo roadmap as posted on EDN China (in Chinese).
They have plenty of wireless RISC-V MCUs in the pipeline with BL606/BL608P featuring WiFi, Bluetooth, and Zigbee connectivity plus a DSP and AI accelerator, as well as BL808 adding an ISP for camera support. BL702 is designed for the smart home with Zigbee and BLE 5.0, and BL708 is similar but with Bluetooth 5.2 dual-mode (BLE + Bluetooth Classic). They even have a WiFi 6 RISC-V IoT chip (BL616), and other chips for AI edge computing (BL828), support for 2×2 MIMO (BL628), etc…
This looks promising, but we’ll have to see how software support progresses. There’s a developer website but I did not manage to register, and the forums are fairly empty right now, so there’s nothing much happening in public at this time.