TMS570LS0714: Max. slew rate time of input signal

user4707167

Part Number: TMS570LS0714

In the datasheet of TMS570LS09x/07s, table 7.1 tin-slew (the time for a general-purpose input signal to go from VIL to VIH or from VIH to VIL) is 1ns max.

Is it really necessary to have such a short rise time and why? What happens if a standard SPI signal with e.g. 5 ns rise time is connected? Or is there it an error in the datasheet and should read 1 micro second?

Thanks for any help.

over 7 years ago

0 user4707167 over 7 years ago

Prodigy 245 points

0 Chuck Davenport over 7 years ago in reply to user4707167

TI__Guru 59540 points

Hello User,

This is a confusing specification. The intent is that the maximum slew rate on the input is 1ns not that the maximum rise time be 1ns. I know that this is confusing as we have had others also question this. I have submitted a documentation feedback for this issue so it can be clarified.

With respect to input rise time, the slew can be as slow as you need but consider that when the the input voltage is between VIL and VIH, the value returned from a read of the register will be indeterminate. i.e., it could be a 1 our 0 due to the fact that the voltage level is neither below VIL or above VIH where the level is latched at either a 1 or 0.

0 user4707167 over 7 years ago in reply to Chuck Davenport

Prodigy 245 points

Thanks a lot Chuck. Great support as always!!! Best regards Valentin

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TMS570LS0714: Max. slew rate time of input signal