MC9S08QG8 Datasheet, PDF (109/300 Pages) Freescale Semiconductor, Inc – 8-BIT HCS08 Central Processor Unit

Analog Comparator (S08ACMPV2)
8.2 External Signal Description
The ACMP has two analog input pins, ACMP+ and ACMP– and one digital output pin ACMPO. Each of
these pins can accept an input voltage that varies across the full operating voltage range of the MCU. As
shown in Figure 8-2, the ACMP– pin is connected to the inverting input of the comparator, and the ACMP+
pin is connected to the comparator non-inverting input if ACBGS is a 0. As shown in Figure 8-2, the
ACMPO pin can be enabled to drive an external pin.
The signal properties of ACMP are shown in Table 8-1.
Table 8-1. Signal Properties
Signal
Function
I/O
ACMP– Inverting analog input to the ACMP.
I
(Minus input)
ACMP+ Non-inverting analog input to the ACMP.
I
(Positive input)
ACMPO Digital output of the ACMP.
O
8.3 Register Definition
The ACMP includes one register:
• An 8-bit status and control register
Refer to the direct-page register summary in the memory section of this data sheet for the absolute address
assignments for all ACMP registers.This section refers to registers and control bits only by their names and
relative address offsets.
Some MCUs may have more than one ACMP, so register names include placeholder characters to identify
which ACMP is being referenced.
MC9S08QG8 and MC9S08QG4 Data Sheet, Rev. 1.01
Freescale Semiconductor
109