The $8 Linux Computer • Hacker News Board

Re: The $8 Linux Computer

#21

Post by Tepix » Sat, Dec 17, 2022, 9:38 AM UTC

alexisread wrote: post #20

mmuless22 wrote: post #13

what is the memory management unit supposed to do on embedded computers? I'd rather like one for 5$ without mmu.

This chip has 4 cores, and I believe they all share the same memory bus ie. Each core can access the 64GB ram directly. There is also 768K sram for low power use. Only the RV64 large core has an mmu, the two RV32 cores don't. I think the chip's main use could be robotics- the lowest power core for networking, npu for image processing, the mid core for simple tasks and the large core for Linux and complex tasks eg. Na…

> the 64GB ram

It's 64 MB RAM

Re: The $8 Linux Computer

#22

Post by alexisread » Sat, Dec 17, 2022, 9:44 AM UTC

Tepix wrote: post #21

alexisread wrote: post #20

Earlier quoted context omitted.

This chip has 4 cores, and I believe they all share the same memory bus ie. Each core can access the 64GB ram directly. There is also 768K sram for low power use. Only the RV64 large core has an mmu, the two RV32 cores don't. I think the chip's main use could be robotics- the lowest power core for networking, npu for image processing, the mid core for simple tasks and the large core for Linux and complex tasks eg. Na…

> the 64GB ram It's 64 MB RAM

Ah yes thanks, still pretty good though for on-package for £3-odd (UK price). https://m.aliexpress.com/item/1005004970779483.html

Re: The $8 Linux Computer

#23

Post by hoppyhoppy2 » Sat, Dec 17, 2022, 9:48 AM UTC

etaioinshrdlu wrote: post #10

What is the power consumption of the processor chip (with CPU using and not using radio?) I couldn't find any info on this from its datasheet.

I don't know, but it runs off of a 5V/0.5A power supply if that helps at all.

Re: The $8 Linux Computer

#24

Post by galangalalgol » Sat, Dec 17, 2022, 9:50 AM UTC

teleforce wrote: post #5

There's another post on HN several days back with similarly price Sipeed M1s that's based on the same Bouffalo Lab BL808 RISC-V SoC module including NPU providing support for WiFi/BL, 802.15.4 Zigbee connectivity and interfaces such as UART, I2C, SPI, etc: $10.80 RISC-V AIoT module supports Linux: https://news.ycombinator.com/item?id=33874032 EDIT: This is the official website for the Sipeed M1s showcasing the specs…

Is there anyway to use the NPU (blai-100) on this thing? That seems like bsp territory.

Re: The $8 Linux Computer

#25

Post by unwind » Sat, Dec 17, 2022, 9:58 AM UTC

mmuless22 wrote: post #13

what is the memory management unit supposed to do on embedded computers? I'd rather like one for 5$ without mmu.

It allows you to use Linux, which is a sellable bullet point. Might also be useful sometimes, and allow knowledge sharing, increase portability and so on.

Re: The $8 Linux Computer

#26

Post by psychphysic » Sat, Dec 17, 2022, 9:59 AM UTC

My VisionFive2 just arrived last weekend and I've got the simple buildroot image running.

That was about 10x as expensive but probably more bang per buck.

Re: The $8 Linux Computer

#27

Post by reaperducer » Sat, Dec 17, 2022, 10:02 AM UTC

The form factor is similar to the old Onion SBC, but more expensive and less capable.

The Onion was $5, and included a proper serial interface, an SD card slot and wifi. It might have also had Bluetooth, but I'm not sure as this was seven years ago.

It was a great little machine. Very promising to have an entire Linux machine the size and shape of a 6502.

Alas, the company that made it put out a firmware update that made them act unpredictably, then another that ended up bricking machines. And at a cost of $5, there was no margin for customer support. The last time I looked into it, several years ago, the company appeared to be in pivot mode.

There was a vibrant emerging market of tiny SBCs in the years before COVID. Now everything is Raspberry Pi and Arduino. If you can get one.