External Signal Description; Register Definition - ROHS MC9S08QE128 Reference Manual

Internal
Reference
ACMPx+
ACMPx-
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
the ACMPxO pin can be enabled to drive an external pin.
The signal properties of ACMP are shown in
Signal
ACMPx-
ACMPx+
ACMPxO
9.3 Register Definition
The ACMP includes one register:
• An 8-bit status and control register
Freescale Semiconductor
ACBGS
ACME
+
-
Comparator
Figure 9-2. Analog Comparator (ACMP) Block Diagram
Table
Table 9-1. Signal Properties
Inverting analog input to the ACMP. (Minus input)
Non-inverting analog input to the ACMP. (Positive input)
Digital output of the ACMP.
MC9S08QE128 MCU Series Reference Manual, Rev. 2
Internal Bus
Status & Control
Register
Interrupt
Control
9-1.
Function
Analog Comparator (S08ACMPV3)
ACMPx
INTERRUPT
REQUEST
ACIE
ACF
ACOPE
ACMPxO
Figure
I/O
I
I
O
9-2,
171