ARM Technical Support Knowledge Articles

I/O PINS DON'T TOGGLE DURING COMMUNICATION

Applies to: uVision Debugger

Answer


Information in this article applies to:


QUESTION

I have used the built-in Logic Analyzer to verify the I/O port pin toggling of the serial UART data output. First, I thought that my program was having a problem, but when I tried it in real hardware, it worked fine. Does the port pin not toggle in the simulation?

ANSWER

The µVision simulator simulates the timing and logical behavior of serial communication protocols like UART, I2C, SPI, and CAN. But it does not simulate the I/O port toggling of the physical communication pins on the I/O port.

To provide fast simulation speed and optimum access to communication peripherals, the logic behavior of communication peripherals is reflected in virtual registers that are listed with the DIR VTREG command. This has the benefit that you can easily write debug functions that stimulate complex peripherals.

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Article last edited on: 2004-06-30 19:06:46

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