Customer would like to get information on the acceptable quality of the signal from key performance indicators on the microcontroller perspective on the receive side of the communication signal.
The datasheet does not provide acceptance criteria if the input signal Rise and Fall time as a percentage of the overall clock frequency/ Clock Low/High duration perspective
What would be the timing requirements accordingly:
Diagram |
Measurements |
Acceptance criteria |
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This diagram shows horizontal cursors at 20% and 80% of the signal amplitude. The fall time measurement is captured as 11.6ns |
Please provide an acceptable Fall time range |
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This diagram shows the same signal measuring Clock High duration, which is 83.2ns |
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This diagram shows horizontal cursors at 20% and 80% of the signal amplitude. The fall time measurement is captured as 10ns |
Please provide an acceptable Rise time range |
The customer will be using a variety of peripherals which include I2C, SPI, UART, Ethernet, FlexIO an others. Can NXP provide a white paper or calculator for determining this data for each peripheral.
It is not being so explicitly defined unless it is required by certain peripheral, otherwise it is stated in device datasheet. With this device I see such specification in LPSPI module.
In other aspect in is just CMOS with hysteresis, length of edges is not important unless it affect setup/hold time or other AC characteristic of specific peripheral.