SPI Level Shifting (5v to 3.3v) for Arduino to USB Host Shield Mini

Using Arduino Project Guidance
#1

Hi,

I'm trying to use a CD4504B (CMOS Hex Voltage-Level Shifter) to convert Arduino 5v SPI signals to 3.3v for my Chinese USB Host Mini board.

I've been looking at the SPI signals from the Arduino (5v) SPI lines and they show up in my 8channel logic analyzer just fine.

I then switched the logic analyzer input to the 3.3v output lines of the CD4504B and it doesn't "see" any data.

If I feed the logic analyzer 3.3v directly it shows up as a high signal. If I feed the logic analyzer GND directly it shows up as a low signal.

If I feed +5 directly to an input pin on the CD4504 it outputs 3.3v as expected.

I am baffled as to why the output of SPI signals through the CD4504B isn't showing up.

My current assumption is that the CD4504 is not capable of "switching" fast enough to properly translate the SPI signals.

Any thoughts or next steps?

#2

kpw:
My current assumption is that the CD4504 is not capable of "switching" fast enough to properly translate the SPI signals.

Well, the "CD" version is certainly wrong - you need the 74HC4054 for microprocessor work.

#3

Thanks for your quick response. Glad to hear there is something else to try instead.

Would like to know a little more detail on why "CD" is wrong?

Thanks! I'm fairly new to electronics as you might have guessed.

I was using this chip because of another article I saw here:

#4

FYI - Yes, using a CD74HC4050E instead made it work perfectly. Thanks.

#5