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Topic: 74HCT244P for controlling several LEDs (Read 464 times) previous topic - next topic

kunze

Oct 03, 2013, 06:48 pm Last Edit: Oct 03, 2013, 07:54 pm by kunze Reason: 1
Hi!

I'm new to both Arduino and electronics, so I went to my local store selling electronic components and asked for something that can expand the number of PWN outputs so that I can connect eg. a 8x8 RGB matrix to my Arduino without taking up too many outputs and that would allow me to dim/fade LEDs.

They sold me a bunch of 74HCT244P's to do the job so I went home and started googling how to use these things. But I haven't been able to find a single example using these chips, only ones using the 74HC595, xxxx164 etc.

I've found these schematics: http://www.nxp.com/documents/data_sheet/74HC_HCT244.pdf

The 74HCT244 seems nothing like the 595 or 164, there is no reset pin, no clock pin etc., all I can see is 8 inputs and 8 outputs and a way of enabling/disabling writing.

So I've now ended up concluding that these are probably of no use for what I need - or am I mistaken?

Could someone enlighten me on what these can be used for and a bit of guidance on how to use them?

Thanks a bunch!

/ Simon

CrossRoads

Yes, '244 is a bus buffer chip, use between Arduino and LED. Has less current capability than the '328, just 6mA vs 20mA tho, so not really a good LED driver.

Its real use is to seperate controllers to allow one (of 2 or more) to access an address bus, data bus, control bus and control a peripheral device (say a shared SRAM).

You really want chips like TLC5490, WS2803, shift in PWM data and let the chip control the LED current.
Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

kunze


You really want chips like TLC5490, WS2803, shift in PWM data and let the chip control the LED current.


Thanks for your reply!

Okay so happy to find out that I'm not completely stupid here  :smiley-eek:

I asked in the store for the TLC5490 as that seems to be what people are using, but they had none of those in stock and gave me these in stead... Hmm... I'll pay them another visit!

Thanks.

/ Simon

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