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Interfacing 5v (Rd/Tx) to 3.3v (Tx/Rx)

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Well-Known Member
The 74HCT125 is awesome for SD since its a QUAD piece. You might find it more usefull using that part. The SN74LVC2T45 is a OCTAL part which may be a overkill.

I think its ok if you connect the 3.3v output to a 5v input aka 3.3v Tx pin to micro but for the input pin use that IC. You could use the IC for both if you wish.

I never tried this but maybe you can convert the 3.3v logic to a 5v logic:
I assume you need to setup like

1A = 3.3v
1Y = 3.3v Rx Pin on GPS module
1OE = TX on PIC

2A = 5v
2Y = Rx on PIC
2OE = 3.3v TX Pin on GPS module

If im wrong please correct me. :D

Be aware that this IC : "outputs enable inputs (OE = active LOW)"

A "74AHC126" would be the best for this i think
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New Member
I will not recommed the HCT,HC series buffer.And 74HCT125 is not a level translator.Use level translator only.Level translator only solves your problem
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