29 votes

Use cases for RAM-less microcontrollers

It is very low power. The chip does have RAM: 32 registers that are preserved over power-down mode, which draws less than 1µA. It also has EEPROM. You'd typically use a chip like this for data logging ...
Simon Richter's user avatar
16 votes

Use cases for RAM-less microcontrollers

Such very low end microcontrollers are pretty much intended exclusively for high volume commercial consumer electronics where the price is everything and one can compromise a lot about quality and ...
Lundin's user avatar
  • 19.9k
14 votes

Discrete logic design

I'm not a professional electronics engineer at all (actually just a beginner), but my few cents are that dedicated discrete logic ICs should only be used if timing is important or if it is a ...
Michel Keijzers's user avatar
14 votes
Accepted

Discrete logic design

Discrete logic design won't be fully phased out. There will always be applications where using a discrete logic IC is preferable. As has been pointed out, speed is a big advantage, although in a lot ...
MCG's user avatar
  • 11.9k
13 votes
Accepted

Counter for 20 GHz clock

15 years ago I designed a two parameter digitizer (energy and time) to measure time of flight. For this system I used a constant current source into a cap held in reset by a JFET. On receiving the ...
mike ingle's user avatar
13 votes

Use cases for RAM-less microcontrollers

The point is not about having no RAM. The point is, you can use it in any application where you need some kind of chip that does very simple things cheaply, but such an ASIC does not already exist or ...
Justme's user avatar
  • 143k
12 votes
Accepted

Is it possible to replicate the ENIAC using logic gates

The ENIAC used logic gates, they were just made up of vacuum tubes. The ENIAC had thousands of them. 6,550 out of the 18,800 tubes in the computer (circa 1946) were dual-triode 6SN7GTs. Each tube was ...
tcrosley's user avatar
  • 48k
12 votes

Accurate quadrature decoding without external clocking

Possible XY problem? tl, dr: yes, it's possible to make a simpler, 'accurate', non-clocked quadrature decoder, that is, one that reliably detects all the possible state transitions and infers the ...
hacktastical's user avatar
  • 52.7k
11 votes

Use cases for RAM-less microcontrollers

I've used an ATTINY10 like this, and it's low pin count and very low power. It can't do much, it only fits 1k of FLASH, that's less than 1 thousand instructions. You can barely compile any C code for ...
Jeroen3's user avatar
  • 22.7k
10 votes

Discrete logic design

If you're going to create a commercial product, you really shouldn't choose a design because "it's programmable" or because a more senior colleague proposed it. Instead you should estimate risks and ...
Dmitry Grigoryev's user avatar
9 votes
Accepted

Please explain this price difference

Yes, of course, supply and demand. But let me make a few comments on manufacturer costs. Newer IC's are typically built on newer fabs which can fit more transistors in a smaller area. Because of this, ...
user57037's user avatar
  • 29.3k
9 votes

CPLD is (sometimes) not incrementing counter

Is the trigger input completely asynchronous to the 50MHz clock? If so, it probably violates the setup and hold time requirements from time to time. You need to ...
Dave Tweed's user avatar
  • 172k
8 votes

MITM on I2C Bus

I think that attempting cutsey hacks like you have been is asking for trouble, with exactly the kind of symptoms you are running into. You are basically trying to cheat and hope you don't get caught. ...
Olin Lathrop's user avatar
8 votes

Can I use C language to program a CPLD/FPGA?

Generally you can. There is free SystemC for HLS(High Level Synthesis). HLS is getting more and more popular but what you have to remember is that you do not program CPLDs /FPGAs using C language, you ...
Al Bundy's user avatar
  • 696
7 votes
Accepted

CPLD is (sometimes) not incrementing counter

Fist of all:Your trigger is coming in a-synchronous to the clock. You must first synchronize it before you can safely use it. The code for that is: ...
Oldfart's user avatar
  • 14.3k
7 votes

Discrete logic design

One aspect the other answers are forgetting is safety. Discrete logic circuits are way more reliable than much more complex microcontroller designs. I helped building a hydrogen prototype car, all the ...
LukeHappyValley's user avatar
7 votes

CPLD based Pierce oscillator

This CPLD has Schmitt trigger inputs so I guess this should be possible. Actually, if it has Schmitt trigger inputs it makes it impossible. A Schmitt trigger would just about guarantee that the ...
TimWescott's user avatar
  • 45.8k
7 votes

Use cases for RAM-less microcontrollers

One application is IR TV remotes. There are ASICs that are designed for this, but maybe your design has some LEDs and the ASICs don't quite do everything you want. 32 bytes of "ram" is ...
9072997's user avatar
  • 171
7 votes

Use cases for RAM-less microcontrollers

First off, such MCUs are almost used exclusively where assembly-only is involved. I almost never use them in combination with a C compiler. Second, such MCUs are often used for cost-sensitive ...
periblepsis's user avatar
  • 7,560
6 votes

Counter for 20 GHz clock

As someone already pointed out, there are dedicated ICs for that purpose. If you want to do it on your own a possible approach would be to use so called Vernier delay lines. You have two delay lines ...
Mario's user avatar
  • 8,195
6 votes

Counter for 20 GHz clock

Some long while ago, as a thought experiment, I 'designed' a time capture FPGA. It had a ring oscillator, conventional other than the fact it had 41 inverters. The period was thus much much lower ...
Neil_UK's user avatar
  • 165k
6 votes
Accepted

PAL data with ADC?

It is not practical to resolve an NTSC or PAL type analogue video data into a digital format using a typical microcontroller A/D converter. The equivalent pixel density of the analogue signal is 13.5 ...
Michael Karas's user avatar
6 votes
Accepted

Can an EPROM be "refreshed" without UV erasing?

When the EPROM is erased, all the bits are typically read as ‘1’, so each byte is 0xFF. That is the way they will tend to age, with time and high temperature or radiation. If you don’t have access ...
Spehro Pefhany's user avatar
6 votes
Accepted

How do you cast an integer as a time in VHDL?

multiply (or operate otherwise) by the time unit constant t_per : time := (1 / input_frequency * 1000000000) * 1ns; (or variations thereof)
CapnJJ's user avatar
  • 935
6 votes
Accepted

CPLD based Pierce oscillator

I do not recommend this approach. You may get some circuit to oscillate under some conditions but you may very well have problems with jitter, unreliable startup and off frequency operation. You ...
Michael Karas's user avatar
6 votes
Accepted

Accurate quadrature decoding without external clocking

The original question asks for a circuit which extracts the direction information from a pair of encoder signals (i.e. quadrature signals). The question asks that the circuit not employ clocks, nor ...
Math Keeps Me Busy's user avatar
6 votes

Use cases for RAM-less microcontrollers

There isn't much qualitative difference between a microcontroller with a handful of registers and 16 bytes of "RAM", versus one with 32 registers and zero bytes of RAM. Programmable logic ...
supercat's user avatar
  • 46.6k
5 votes

Dividing numbers on an FPGA

Our Open-Source PoC-Library has a multi-cycle division IP core, which can be synthesized as a pipeline. The bit count of the dividend and divisor as well as the radix can be configured to the users ...
Paebbels's user avatar
  • 3,907
5 votes

74LS161 in program counter circuit jumps clock cycles

As far as I can see, you don't have any power supply decoupling capacitors anywhere on your collection of breadboards. It's no wonder it's "touchy" and sensitive to glitches. You should put about 100 ...
Dave Tweed's user avatar
  • 172k

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