Search found 224 matches

by Garth
Wed Jun 17, 2020 8:47 am
Forum: Programming PIC's with Swordfish Basic
Topic: I2C LCD Displays with PCF8574
Replies: 6
Views: 170

Re: I2C LCD Displays with PCF8574

It sounds pretty easy. If its I²C clock rate is limited to 100kHz (max of 12.5KB per second), you won't be overrunning the LCD's ability to keep up for most instructions, especially with the 4-bit interface. I should probably get some of those ICs to have on hand and play with.
by Garth
Wed Jun 17, 2020 6:48 am
Forum: Programming PIC's with Swordfish Basic
Topic: I2C LCD Displays with PCF8574
Replies: 6
Views: 170

Re: I2C LCD Displays with PCF8574

Thanks. I've usually used these LCDs in 4-bit mode, with 6 lines (just grounding the R/W, which just means you have to give it enough delay that you know each instruction is finished, since you can't poll it). I have working sample code in different forms at http://wilsonminesco.com/6502primer/LCDco...
by Garth
Wed Jun 17, 2020 4:47 am
Forum: Programming PIC's with Swordfish Basic
Topic: I2C LCD Displays with PCF8574
Replies: 6
Views: 170

Re: I2C LCD Displays with PCF8574

That looks nice. Do you sell the I²C module? I don't see any way to buy it. Actually, I'm sure it could be used for a lot of other things besides an LCD, right? And there are undoubtedly a lot of I²C-to-parallel adapter ICs on the market, probably from Maxim and others; but this one is already made ...
by Garth
Tue Apr 07, 2020 7:35 am
Forum: The off topic lounge
Topic: great danger from cell-phone use
Replies: 25
Views: 21145

Re: great danger from cell-phone use

It would be interesting to see the results of an experiment (or multiple experiments) that have all the correct control measures in place.
Dr. Devra Davis with data on studies with controls:
https://www.youtube.com/watch?v=BwyDCHf5iCY
by Garth
Fri Feb 14, 2020 4:19 pm
Forum: Brads Projects University
Topic: soldering SOJ (& similar) parts without special equipment
Replies: 7
Views: 11434

Re: soldering SOJ (& similar) parts without special equipment

Here's another one, an SOIC. These were taken with a very cheap camera. First I tack one corner, and get the IC really straight, then tack the opposite corner, and again make sure I haven't rotated it out of being straight. Then I do the two remaining corners. Then I flood a whole side with solder, ...
by Garth
Wed Dec 11, 2019 6:13 am
Forum: PCB Design
Topic: Analysis of the basic process and steps of PCB circuit board design
Replies: 1
Views: 6534

Re: Analysis of the basic process and steps of PCB circuit board design

I find a lot of problems with the post above. For starters, I would recommend going through Dr. Howard Johnson's articles indexed at https://web.archive.org/web/20120302190123/www.sigcon.com/Pubs/pubsKeyword.htm . He is quite an industry guru, and the author of "High Speed Digital Design: A Handbook...
by Garth
Tue Sep 17, 2019 3:06 pm
Forum: The off topic lounge
Topic: CHEAP board houses?
Replies: 6
Views: 7958

Re: CHEAP board houses?

There are so many now. I've been using DirtyPCBs , and getting excellent prices, no quality problems, and relatively fast service. I've been using them for hobby boards and for prototypes of the simpler ones of our products at work. (When we're ready for production, we go to more-professional board ...
by Garth
Wed Apr 24, 2019 3:04 pm
Forum: Brads Projects University
Topic: Mixed Voltage Systems: Interfacing 5V and 3.3V Devices
Replies: 8
Views: 13882

Re: Mixed Voltage Systems: Interfacing 5V and 3.3V Devices

I see now the link in the head post, http://www.savagecircuits.com/content.php?85-Mixed-Voltage-Systems-Interfacing-5V-and-3-3V-Devices, is dead. I don't remember what was in the original, but one it might have been is http://nutsvolts.texterity.com/nutsvolts/201104/?folio=46&pg=46#pg46, and another...
by Garth
Thu Apr 04, 2019 2:10 pm
Forum: The off topic lounge
Topic: great danger from cell-phone use
Replies: 25
Views: 21145

Re: great danger from cell-phone use

Brussels Becomes First Major City to Halt 5G Due to Health Effects
http://www.greenmedinfo.com/blog/brusse ... th-effects
by Garth
Thu Apr 04, 2019 1:25 pm
Forum: Great video clips
Topic: Vulcan-74: A 6502 Retro MegaProject
Replies: 8
Views: 19009

Re: Vulcan-74: A 6502 Retro MegaProject

Brad, how nice to see you here! There are a few 6502.org members here as well. Two who immediately come to mind are BigEd and Dr Jefyll (Jeff Laughton). I don't know how often they check in. This forum used to be more active, apparently when Brad Slattery (the owner) was having his students post pro...
by Garth
Fri Nov 30, 2018 8:58 am
Forum: PCB Design
Topic: Beginner PCB design for LED clock
Replies: 1
Views: 2506

Re: Beginner PCB design for LED clock

A small board like that with 74HC logic will be more forgiving than some. The matter of grounding, ground bounce, bypassing, transmission lines, terminations (which you definitely do not need on this board), etc. is complex and is discussed in a 6502.org topic at http://forum.6502.org/viewtopic.php?...
by Garth
Thu Nov 29, 2018 9:48 am
Forum: The off topic lounge
Topic: Comments on a metronome schematic and board?
Replies: 1
Views: 2836

Re: Comments on a metronome schematic and board?

It's pretty clear that you're trying to sell PCBGOGO services here. It's ok though, since at least you're on topic and not giving us unrelated spam like we often have to delete. I was not able to download the dropbox files without starting an account, which I don't really want to do. You can attach ...
by Garth
Tue Oct 02, 2018 4:37 am
Forum: PCB Design
Topic: Circuitmaker
Replies: 8
Views: 9159

Re: Circuitmaker

I just got an email from Digi-Key saying they now had a free online symbol and footprint library for KiCad, at https://www.digikey.com/en/resources/design-tools/design-tools#kicad . On a related note, I just finished my first dense design of parts on both sides. Up until now, I have sometimes put ju...
by Garth
Mon Aug 06, 2018 11:23 am
Forum: The off topic lounge
Topic: great danger from cell-phone use
Replies: 25
Views: 21145

Re: great danger from cell-phone use

Health Concerns from Wi-Fi In Schools FOX 5 News Featuring EHT's Cell Phone Absorption Research (six-minute video): https://www.youtube.com/watch?v=fk17yuFwy7M Wi-fi OFF Switches Installed In Finnish School To Reduce Wireless Radiation Exposure to Children (article): https://ehtrust.org/wi-fi-off-sw...
by Garth
Wed Jul 04, 2018 8:16 am
Forum: PCB Design
Topic: JLCPCB - PCB only $2 :)
Replies: 7
Views: 10367

Re: JLCPCB - PCB only $2 :)

I don't remember if I saw it or not. It seems like I have to have seen it, since I check the forum for new posts every day. I should have recommended putting thermal relief around the pads that go to the plane around them. If you wave-solder it and never need to repair or rework it, it's no problem ...