Oh yes, you are right! The shielding looked different, so I thought they must be new (and they came up when searching for ESP32-C3, thanks fuzzy search…)
I’ll remove that post to avoid confusion.
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Fireduino
I was gathering info about multi Core MCUs and discovered that Rockchip, better known for their multimedia application processors, also has a line of MCUs. Those seem to be focused on audio processing, RKNanoC is a single Cortex M3, but there is also the Dual Core RKNanoD:
- 2x Cortex M3 (one core at 250 MHz, the other at 500 MHz)
- 640k RAM for the slow core, 384k for the fast one
- APE, FLAC, OGG, and MP3 decoder
- firmware on external flash
On a quick glance I found no public documentation though. It’s also a rather old board / MCU, so this is more for curiosity’s sake.
Also 2nd the Sparkfun boards- the Edge is just one of the Apollo3 based boards. Some seem to have UART available. I bought an Artemis Nano for $14.95. These are all the boards: https://www.sparkfun.com/search/results?term=apollo3 +A La Carte could be used for designing boards with custom components. https://alc.sparkfun.com/ They recently released a LoRa board, but I plan to use the Nano before a larger one.
RISC-V keeps on delivering on it’s promise of diversifying the chip market.
Bluetrum has announced the AB5301A MCU designed for audio players.
It’s available on the AB32VG1 board and has support in RT-Thread.
- 120 MHz RISC-V
- 192k RAM
- 1 MiB Flash
- Bluetooth 5.0
- FM radio receiver
- USB 2.0 Host & Device support
- 16 bit DAC, up to 48 kHz
No pricing or availability information yet.
This might be a low hanging fruit based on EFR32MG21:
Zigbee 3.0 USB Dongle
itead, $6.99
- 80 MHz Cortex-M33 (EFR32MG21A020F768IM32)
- 768k Flash
- 64k RAM
- 802.15.4 radio
- BLE radio
I intent to assign porting RIOT to the RPi Pico as a software project. So if anyone is interested in this and willing to join forces, give me a ping.
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There is also now an Adafruit Feather wtih the RPi Pico chip: The Feather RP2040. Pretty affordable compared to other Feathers too.
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Aaaaand it’s out of stock, wonder how long that took
From Europe it makes more sense to order via Mouser anyways 
I add the nrf53 here, due to an issue we have on this forum.. The nRF5340 DK is a development board for the MCU.
Microchip just releases a new WiFi MCU -> WFI32E01PC using a PIC32MZW1
more info here -> https://www.microchip.com/Developmenttools/ProductDetails/EV12F11A
LoDev S76S. Its based on AcSIP LoRaWAN module S76S . AcSIP seems to have good inventory even in these times of silicon shortage. Once ported, maybe a good option for LoRaWAN prototyping.
yes the adafruit rp2040 would be my favourite target - with a plug-in transceiver thats already supported
There are more RISC-V boards available:
ESP32-C3-DevKitM-1
Mouser, 6.78 €
- 160 MHz RISC-V
- 384k ROM + 4 MiB SPI Flash
- 400k RAM
- WiFi & Bluetooth
Hi3861 Development Board
AliExpress, $26
- 160 MHz Hi3861
- 288k ROM + 2 MiB SPI Flash
- 352k RAM
- WiFi
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So very confusing for espressif to create a RISC-V system with the name “ESP32”! (But at that price… wow)
The Hi3861 is now also available on the cheaper HarmonyOS development for $11.
But there are also new chips: QinHeng Electronics replaced the Cortex-M0 on their designs with a RISC-V CPU to create e.g. the CH573 MCU:
It’s a very low-end chip, but comes with BLE 4.2 and USB. There is a dev board available:
CH573 Devboard
AliExpress 17€
- 20 MHz RISC-V IMAC
- 18k RAM
- 512k ROM
- BLE 4.2
- USB 2.0
M5Stamp C3
This is a neat little board with an ESP32C3, which is the new RISC-V based member of the ESP32 family
m5stack $6
- 160 MHz RISC-V
- 400k RAM + 8k RTC RAM
- 384k ROM + 4 MiB Flash
- 2.4 GHz WiFi (b/g/n)
- Bluetooth 5
via CNX Software
NUCLEO-U575ZI-Q
ST released their new line of ultra-low power MCUs accompanied by the usual dev boards like the NUCLEO-U575ZI-Q.
- STM32U575ZI (160 MHz Cortex-M33)
- 786k RAM + 2k backup RAM
- 2 MiB ROM
- 19.5 μA/MHz in RUN mode, 440 nA in Standby mode with RTC running
Mouser 20€
You can now buy boards with the BL702 (RISC-V, 802.15.4 radio) based on the XT-ZB1 module:
AliExpress 2€
- 144MHz RISC-V
- 132KB RAM
- 192KB ROM
- BLE 5.0
- IEEE 802.15.4
There is an SDK with an IEEE 802.15.4 example, the radio driver appears to be a blob though 
sipeed released a micro sized board off the BL702 chip… apparently they are developing their own env… so that now the wireless drivers and blob should now be accessible? https://twitter.com/SipeedIO/status/1598121931798376450
Hi there!
I found a cheap chinese MCU board with WiFi+Bluetooth support:
MicroWinner W801. Based on C-SKY architecture. 2.5$ Aliexpress.com
- 240MHz C-SKY MCU
- 288RAM + 2MB Flash
- PSRAM SPI/QSPI
- WiFi
- Bluetooth BLE 4.2
- SDIO
- Encrypting features: RSA/AES/RC4/DES/3DES/RC4/SHA1/MD5/CRC8/CRC16/CRC32/TRNG
- RTC module
SDK with examples: github
Chinese RM is difficult to read but the board has many features for RIOT. Also exists W806 version without wireless interfaces and W800 - only chip in QFN32 with WIFI+BLE.
