
Chapter 9 Analog Comparator (S08ACMPV3)
MC9S08DN60 Series Data Sheet, Rev 3
164
Freescale Semiconductor
9.1.4
Block Diagram
The block diagram for the analog comparator module is shown
Figure 9-2.Figure 9-2. Analog Comparator (ACMP) Block Diagram
9.2
External Signal Description
The ACMP has two analog input pins, ACMPx+ and ACMPx
and one digital output pin ACMPxO. Each
of these pins can accept an input voltage that varies across the full operating voltage range of the MCU.
As shown in
Figure 9-2, the ACMPx- pin is connected to the inverting input of the comparator, and the
ACMPx+ pin is connected to the comparator non-inverting input if ACBGS is a 0. As shown in
Figure 9-2,the ACMPxO pin can be enabled to drive an external pin.
The signal properties of ACMP are shown in
Table 9-1.Table 9-1. Signal Properties
Signal
Function
I/O
ACMPx-
Inverting analog input to the ACMP.
(Minus input)
I
ACMPx+
Non-inverting analog input to the ACMP.
(Positive input)
I
ACMPxO
Digital output of the ACMP.
O
+
-
Interrupt
Control
Internal
Reference
ACBGS
Internal Bus
Status & Control
Register
A
CMOD
set
A
CF
ACME
ACF
ACIE
ACOPE
Comparator
ACMPx
INTERRUPT
REQUEST
ACMPx+
ACMPx-
ACMPxO