Recent Posts

1

FPGA / Re: A FPGA Audio System in raspberrypi size and open source later.

« Last post by antercreeper on Today at 02:57:42 am »

Sorry for my bad English  :'(

I use TMP435 to monitor the diode of the FPGA and 1. trigger reset of your design while too hot 85 degrees 2. cut the Power while overheated, maybe 100 degrees.

2

Buy/Sell/Wanted / Re: SALE (AU/NZ): Multicomp Pro MP710086 (Owon P4305 rebadge) at element14

« Last post by EvgenyG on Today at 02:50:45 am »

If you are interested in it, perhaps check the manual and some reviews. I'd want to know if it had good controls and was easy to set voltage and current.  Sometimes power supplies with a single voltage knob and single amp knob per channel can be tricky to set precisely (if that is important to you).

Looks like it has 1 turn potentiometers which means coarse setting for Voltage/Amps. I was thinking about upgrading from TENMA but now I'm thnking, even though the build quality would be much better, the digital V control and the ability to lock front panel is very important to me.
The analog pot with 10 deg per volt setting is too coarse, one silly mistake and magic smoke comes out your DUT Price is a bargain though.

3

Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement

« Last post by dj_holmes on Today at 02:40:41 am »

Oh wow so the normal 74HC4046 is better!?!

SN74LV4046A  Optimized Power-Supply Voltage Range From 3 V to 5.5 V

4

Microcontrollers / Re: A couple questions about Milk-V Duo boards

« Last post by brucehoult on Today at 02:40:05 am »

More progress today:

"Daniel aka CyReVolt 🐢: Transferring code to the CVITek 1800B worked with my tool. There was no output on the UART though. I'll see if the SRAM address is different, which isn't described in the manual. UART0 seems to have the same base address per the manual."

"plat/cv180x/include/platform_def.h
296:    #define VC_RAM_BASE 0x3BC00000 // Shadow_vc_mem"

"Daniel aka CyReVolt 🐢: aha aha - 0x3BC00000 - neither "VC RAM" nor that address is mentioned in the manual"

"Daniel aka CyReVolt 🐢: THAT WORKS! VROOM VROOM! 🥳"

"I have now successfully run my own code on
- Duo (CV1800B)
- Duo 256M (SG2002)
- Duo S (SG2000)

The CV1800B has its SRAM at a different base address.
UART0 is mapped to the same address for all three."

His "own code" is written in Rust. Blergh for some people, ++ for others :-)

A note on chip names and companies ... Sophgo bought Cvitech a year or two ago, so CV1800B and SG200* share lineage.  Also, a well informed Chinese person on Telegram said a couple of days ago that Sophgo and Radxa are parts of the same company, or fall under the same umbrella company (Bitmain?). I just found this repo, which lends support to this: https://github.com/radxa/bm-bootloader-arm64

5

Beginners / Re: Replacing SRAM IC with Flash

« Last post by VEGETA on Today at 02:38:15 am »

first time i read about picram thing, definitely weird! an mcu acting as a ram! will look into it for sure.

however, i wanted it to be as simple as possible... meanwhile i got this suggestion (prices are per 100 finished unit):

memory IC: 2.5-3$
counter IC (74HC393): 0.3$
4:16 IC (74HC154BQ): 0.6$
LEDs (16 per unit) example (B1591UY--20C000112U1930): 1.8$ for 1600 pieces = 100 finished units

around 5$

this is without PCB and enclosure.

for enclosure i would go with 3d printing, here is a 3d model for the shell i found: https://grabcad.com/library/nintendo-64-controller-pak-1

how much would this cost for smooth black color? can it be 1$ per unit??

i read about injection molding but using a 3d printed mold... how realistic would this be to get about 1-2$ total cost per unit.?

6

Test Equipment / Re: Siglent SDS3000X HD and upgraded SDS1000X HD

« Last post by DaneLaw on Today at 02:30:22 am »

24h later.....
Unpacked, more pictures will follow in the days to come.
The fact that the display foil is not present and neither are the front dust caps is not a problem, but it was different with the 2104XHD.

As it turned out today, I wouldn't have been able to get one either, despite ordering over 3 months ago.
They sent me their own demonstration device by mistake (hence the missing display foil and dust caps), but I can keep it until a new one is actually sent out.

This Batronix "mistake" where they seem to ship you their own demo-unit as your new retail unit..
Was it you, that asked Batronix why your SDS3000X HD were missing certain new clothing factors, like screen-foil etc, and then they explained you, that "ups we made a mistake  and shipped you our demo unit" or was it Batronix that gave that info without any inquiry and we made a mistake and its only a temporary and you will get a brand new model when its in stock?

7

Manufacturing & Assembly / Re: LPKF Protomat S42: Machine "shock absorber"/"stroke limiter" tuning

« Last post by rsaxvc on Today at 02:27:27 am »

I think I found it! Stashed away in a different bit-box, there was one unmarked drill bit with a pink ring around it, 43mm long, 2.95mm diameter. The reference strips are 4.5mm thick, the reference strip slot is 5mm deep past the bed surface, so if a 38mm bit is almost touching the bed, a 43mm bit would leave at least .5mm clearance from the bottom of the slot, without adjusting the Z-stage-limiter. I've also found a short piece of old reference strip with a hole in it! What a find! A short bit of plastic! But the hole in there is ~3.4mm deep, and when I drilled with the 43mm bit, I got a ~3.3mm deep hole that matches the reference pin well. I think I'm all set. Thanks!

8

Beginners / Re: LM317 Based Digitally Controlled Power Supply

« Last post by EthannCraftt on Today at 02:25:23 am »

Thanks all for replying!! I got caught up in my high voltage work and was a little busy with that.

I'm not necessarily opposed to replacing the lm317 with discrete components, I just thought it would be a fun design challenge and a nice way to use the ones I had on hand

I did plan on adding a feedback on the output to the microcontroller (and one across the 1ohm resistor from the current limiter circuit), I just didn't know how to integrate that into a digital schematic.

The main problem that I've noticed based on the replies was the fact that inputing a voltage puts the internal voltage refrence in series, and to be frank I doubt the accuracy of my own voltage input. How would I go about voltage regulation with PWM another way that doesn't have this issue? I couldn't figure it out with my tinkering in simulation software. Can it even be done while maintaining use of the LM317?

Again, I would be perfectly okay with changing out the voltage regulator with discrete circuitry, so long as it's accurate(ish). Thanks!

9

Projects, Designs, and Technical Stuff / Re: PC74hct4046ap Replacement

« Last post by BrianHG on Today at 02:22:16 am »

Hi, are you saing my current PC74hct4046ap is a little less noise than 74HC4046? If so is the SN74LV4046AN even less noisy?   

HC4046 should be a little less noisy.
LV4046 isn't designed for 5v supply, it's designed for 3.3v supply and below.  (Don't quote me here, double check the data sheet.)

10

Microcontrollers / Re: Routines to convert binary to BCD in C code

« Last post by Nominal Animal on Today at 02:15:52 am »

Is there an actual problem that's trying to be solved here?

Not really.  Binary to decimal conversion is considered "slow" and requiring "surprisingly much" machine-level code, compared to arithmetic operations, so these can be useful in some cases, but that's about it.

Library implementations, especially various printf() implementations, are written for correctness and not for efficiency, so when you work with smaller microcontrollers, especially 8-bit ones (AVRs, PICs, 8051s), a custom implementation can be useful.  More annoyingly, most standard library functions use arbitrary precision arithmetic and dynamic memory allocation during conversion of floating-point numbers.

Even on fully hosted C environments, it turns out that if you read numeric data from text files, the standard C library string-to-number conversions (strtod(), strtol(), scanf() and their variants) become the bottleneck, when you have enough (megabytes) of data.  Then, too, "optimized" conversion functions can reduce the load times to a fraction of what they would be using standard C conversion functions.