I’m selecting a level shifter for the APA-102 leds. I know that most people successfully (including me) connected it directly to a 3.3V data pin without shifter. However since I’m designing a PCB it might be smart to keep the official specs in account (Adafruit mentions this also with their Dotstar …

This is what sparkfun have in their 2way level shifter: https://www.adafruit.com/datasheets/BSS138.pdf (I know it’s an Adafruit doc, but the level shifter I buy is from Sparkfun: https://www.sparkfun.com/products/12009 - they have the full Eagle files - so you could easily pick out the single chann…

I tried this Sparkfun breakout, it doesn’t work.

Don’t use the spark fun board - also, remember that for the apa102 you need two channels (clock and data). I think their might be a 4 port version of the 74hct245, but don’t quote me on that.

That said, I believe the “HCT” is the part of the identifier to look for in order to get “fast enough” so what you’re looking at should be good, @Kasper_Kamperman - that said, again, remember you need 2 for the APA102.

The Sparkfun shifter doesn’t work in all situations. @Daniel_Garcia thanks for reminding me that I need two channels for the APA102, I indeed overlooked that. The 4 port version is the sn74hct125d.

@Robert_Atkins doesn’t work, or doesn’t work with LEDs? It seems to work fine with my Imp

@Mike_Thornbury Doesn’t work for the purpose of shifting the Teensy’s 3.3V output to 5V as input for WS2812B LEDs. If you search on the Sparkfun part number here you should find my longer explanation of what went wrong.

Ok, thanks. I just bought a bunch for TTL duties, for which they should be fine.

@Robert_Atkins @Daniel_Garcia @Kasper_Kamperman I came across this article for integrating Adafruit WS2812 NeoPixels with the Electric Imp - they suggest using that exact same level shifter I recommended - are they wrong? Using WS2812 RGB LEDs | Dev Center Electric Imp Internet of Th…

As with running without a level shifter at all, there are plenty of situations where that may work, but may be some situations where they don’t. The 74HCT’s that multiple of us here are recommending are the only solution that hasn’t had any “doesn’t work” situations.

I'm selecting a level shifter for the APA-102 leds.

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marmil (Marc Miller) July 16, 2021, 7:52am 14

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