MC9S08QE128 MCU Series Reference Manual, Rev. 2
172
Freescale Semiconductor
Analog Comparator (S08ACMPV3)
Refer to the direct-page register summary in the memory section of this data sheet for the absolute address
assignments for the ACMP register.This section refers to register 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.
9.3.1
ACMPx Status and Control Register (ACMPxSC)
ACMPxSC contains the status flag and control bits which are used to enable and configure the ACMP.
7
6
5
4
3
2
1
0
R
ACME
ACBGS
ACF
ACIE
ACO
ACOPE
ACMOD
W
Reset:
0
0
0
0
0
0
0
0
= Unimplemented
Figure 9-3. ACMPx Status and Control Register
Table 9-2. ACMPx Status and Control Register Field Descriptions
Field
Description
7
ACME
Analog Comparator Module Enable — ACME enables the ACMP module.
0 ACMP not enabled
1 ACMP is enabled
6
ACBGS
Analog Comparator Bandgap Select — 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.
0 External pin ACMPx+ selected as non-inverting input to comparator
1 Internal reference select as non-inverting input to comparator
5
ACF
Analog Comparator Flag — ACF is set when a compare event occurs. Compare events are defined by ACMOD.
ACF is cleared by writing a one to ACF.
0 Compare event has not occurred
1 Compare event has occurred
4
ACIE
Analog Comparator Interrupt Enable — ACIE enables the interrupt from the ACMP. When ACIE is set, an
interrupt will be asserted when ACF is set.
0 Interrupt disabled
1 Interrupt enabled
3
ACO
Analog Comparator Output — Reading ACO will return the current value of the analog comparator output. ACO
is reset to a 0 and will read as a 0 when the ACMP is disabled (ACME = 0).
2
ACOPE
Analog Comparator Output Pin Enable — ACOPE is used to enable the comparator output to be placed onto
the external pin, ACMPxO.
0 Analog comparator output not available on ACMPxO
1 Analog comparator output is driven out on ACMPxO
1:0
ACMOD
Analog Comparator Mode — ACMOD selects the type of compare event which sets ACF.
00 Encoding 0 — Comparator output falling edge
01 Encoding 1 — Comparator output rising edge
10 Encoding 2 — Comparator output falling edge
11 Encoding 3 — Comparator output rising or falling edge
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