Functional Description - ROHS MC9S08QE128 Reference Manual

Analog Comparator (S08ACMPV3)
9.4

Functional Description

The analog comparator can be used to compare two analog input voltages applied to ACMPx+ and
ACMPx-; or it can be used to compare an analog input voltage applied to ACMPx- with an internal
bandgap reference voltage. ACBGS is used to select between the bandgap reference voltage or the
ACMPx+ pin as the input to the non-inverting input of the analog comparator. The comparator output is
high when the non-inverting input is greater than the inverting input, and is low when the non-inverting
input is less than the inverting input. ACMOD is used to select the condition which will cause ACF to be
set. ACF can be set on a rising edge of the comparator output, a falling edge of the comparator output, or
either a rising or a falling edge (toggle). The comparator output can be read directly through ACO. The
comparator output can be driven onto the ACMPxO pin using ACOPE.
MC9S08QE128 MCU Series Reference Manual, Rev. 2
Freescale Semiconductor 173