4 ms·

Nice, but some examples of (potential) applications would be nice Why just 32 LUTs instead of at least a few hundred? Enough to build a specialized SERDES or

Nice, but some examples of (potential) applications would be nice Why just 32 LUTs instead of at least a few hundred? Enough to build a specialized SERDES or that sort of thing.

Eduard 1y ago
only 32 LUTs also made me scratch my head: what kind of useful things can be made with so few components? Microchip has a web page about "CLB" https://www.microchip.com/en-us/products/microcontrollers/8-bit-mcus/peripherals/system-flexibility/clb https://www.microchip.com/en-us/products/microcontrollers/8-... It includes a creative demo where your browser apparently gets hooked up with a live video stream of an actual running toy hardware setup of a "CLB demo featuring a European traffic light". It's effectively a finite state machine with two red-yellow-green traffic lights. This minimal setup already consumes 26 of the available 32 units. Btw: as a European, let me assure you that our intersections usually consist of more than two traffic lights, include a fault state (blinking yellow light), and feature synchronized pedestrian lights on which we mostly stand until they turn green.
- indrora 1y ago
  > only 32 LUTs also made me scratch my head: what kind of useful things can be made with so few components? There's plenty of options: Memory mappers and Very Simple encryption come to mind. Stuff that is intended to make it Just That Much Harder to get to. Very tiny little finite state machines that handle One Thing.
fake-name 1y ago
These are intended to implement things like specialized communication protocols, or other IO behaviour. Basically, it lets you push a variety of things you'd normally do via CPU polling to the hardware. You could easily do SPI (or something similar, like BiSS-C) in 32 LUTs. The Raspberry Pi Pico modules have something similar (their PIO modules, which support up to 32 instructions - https://dev.to/blues/a-practical-look-at-pio-on-the-raspberry-pi-pico-50j8 https://dev.to/blues/a-practical-look-at-pio-on-the-raspberr...). TI also have a CLB module that's actually even smaller (though they document theirs) - https://www.ti.com/lit/ug/spruir8b/spruir8b.pdf https://www.ti.com/lit/ug/spruir8b/spruir8b.pdf Basically, this is a pretty broadly available IO abstraction.
hinterlands 1y ago
These MCUs are generally targeted for low-power uses and various industrial & automotive stuff. They're not meant for anything high-bandwidth - you'd be using a 32-bit ARM or RISC MCU for that, or a SoC. So, think of it more in terms of offloading simple automation or logic glue to dedicated hardware to save a microamp or keep the state machines tidy.
unwind 1y ago
The smallest members of the family are 8-pin devices with 14 KB flash memory and 1 KB of RAM. They cost around $0.60 in quantities of one. That is typically not a platform where you would need/be able to se a specialized SERDES, since it's not powerful enough to deal with a lot of data. I think the CLB is intended to "eat" some basic latches and/or gates that might en up on boards in industrial/control environments, i.e. push very simple logic stuff with perhaps high demands on timing and reliability into the already-programmable part. Sounds kind of nice, but (as an actual embedded software developer) I would hesitate to commit to a platform that requires using a remote server to generate parts of my code. :|
K0balt 1y ago
It’s on a sub$ part with 8-20 pins and is intended to do what you might otherwise do with a handful of logic gates, for reasons of timing or power consumption. It’s also quite fast compared to the processor in this case. It’s great for handling basic state machine or logic tasks without waking the cpu unless it is needed. It replaces glue logic better than a straight microcontroller… I can imagine a lot of situations where you might install one as universal logic and not even bother to run code on the MCU… like universal glue logic with a built in MCU in case you need it, rather than the other way around.

Nice, but some examples of (potential) applications would be nice Why just 32 LUTs instead of at least a few hundred? Enough to build a specialized SERDES or that sort of thing.

Eduard 1y ago

only 32 LUTs also made me scratch my head: what kind of useful things can be made with so few components? Microchip has a web page about "CLB" https://www.microchip.com/en-us/products/microcontrollers/8-bit-mcus/peripherals/system-flexibility/clb https://www.microchip.com/en-us/products/microcontrollers/8-... It includes a creative demo where your browser apparently gets hooked up with a live video stream of an actual running toy hardware setup of a "CLB demo featuring a European traffic light". It's effectively a finite state machine with two red-yellow-green traffic lights. This minimal setup already consumes 26 of the available 32 units. Btw: as a European, let me assure you that our intersections usually consist of more than two traffic lights, include a fault state (blinking yellow light), and feature synchronized pedestrian lights on which we mostly stand until they turn green.

indrora 1y ago
> only 32 LUTs also made me scratch my head: what kind of useful things can be made with so few components? There's plenty of options: Memory mappers and Very Simple encryption come to mind. Stuff that is intended to make it Just That Much Harder to get to. Very tiny little finite state machines that handle One Thing.

fake-name 1y ago

These are intended to implement things like specialized communication protocols, or other IO behaviour. Basically, it lets you push a variety of things you'd normally do via CPU polling to the hardware. You could easily do SPI (or something similar, like BiSS-C) in 32 LUTs. The Raspberry Pi Pico modules have something similar (their PIO modules, which support up to 32 instructions - https://dev.to/blues/a-practical-look-at-pio-on-the-raspberry-pi-pico-50j8 https://dev.to/blues/a-practical-look-at-pio-on-the-raspberr...). TI also have a CLB module that's actually even smaller (though they document theirs) - https://www.ti.com/lit/ug/spruir8b/spruir8b.pdf https://www.ti.com/lit/ug/spruir8b/spruir8b.pdf Basically, this is a pretty broadly available IO abstraction.

hinterlands 1y ago

These MCUs are generally targeted for low-power uses and various industrial & automotive stuff. They're not meant for anything high-bandwidth - you'd be using a 32-bit ARM or RISC MCU for that, or a SoC. So, think of it more in terms of offloading simple automation or logic glue to dedicated hardware to save a microamp or keep the state machines tidy.

unwind 1y ago

The smallest members of the family are 8-pin devices with 14 KB flash memory and 1 KB of RAM. They cost around $0.60 in quantities of one. That is typically not a platform where you would need/be able to se a specialized SERDES, since it's not powerful enough to deal with a lot of data. I think the CLB is intended to "eat" some basic latches and/or gates that might en up on boards in industrial/control environments, i.e. push very simple logic stuff with perhaps high demands on timing and reliability into the already-programmable part. Sounds kind of nice, but (as an actual embedded software developer) I would hesitate to commit to a platform that requires using a remote server to generate parts of my code. :|

K0balt 1y ago

It’s on a sub$ part with 8-20 pins and is intended to do what you might otherwise do with a handful of logic gates, for reasons of timing or power consumption. It’s also quite fast compared to the processor in this case. It’s great for handling basic state machine or logic tasks without waking the cpu unless it is needed. It replaces glue logic better than a straight microcontroller… I can imagine a lot of situations where you might install one as universal logic and not even bother to run code on the MCU… like universal glue logic with a built in MCU in case you need it, rather than the other way around.