µVISION DEBUGGER: ANALOG COMPARATOR ON AT89C2051

Information in this article applies to:

• µVision Version 2 and Later

QUESTION

On your website you claim to simulate the Analog Comparator for the Atmel AT89C2051. However, in the µVision Debugger this feature is not in your list of peripherals. Do you support this feature?

ANSWER

Yes, the Analog Comparator is simulated.

There is no dialog because there are no SFRs for this peripheral. This comparator uses AIN0 (P1.0) and AIN1 (P1.1) input pins for analog input and uses bit 6 of Port 3 (P3.6) for the comparator output result. Because of this, P3.6 is not available for general purpose I/O. The MCU sets the comparator output (P3.6) to 1 when the analog input AIN0 (P1.0) is greater than or equal to the analog input AIN1 (P1.1).

You can see the function of the Comparator by setting:

AIN0 = 1.0  AIN1 = 1.5 // gives P3.6=0 (verify in the Port3 dialog)
AIN0 = 2.0  AIN1 = 1.5 // gives P3.6=1 (verify in the Port3 dialog)

SEE ALSO

• Device Database: Atmel AT89C2051

Last Reviewed: Friday, January 12, 2007