Datasheet

Chapter 8 Analog Comparator 5-V (S08ACMPV3)
MC9S08SG32 Data Sheet, Rev. 8
120 Freescale Semiconductor
8.6.1.1 ACMP Status and Control Register (ACMPSC)
ACMPSC contains the status flag and control bits which are used to enable and configure the ACMP.
76543210
R
ACME ACBGS ACF ACIE
ACO
ACOPE ACMOD
W
Reset: 0 0 0 0 0 0 0 0
= Unimplemented
Figure 8-3. ACMP Status and Control Register
Table 8-2. ACMP 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 ACMP+ pin as the input to the non-inverting input of the analog comparatorr.
0 External pin ACMP+ selected as non-inverting input to comparator
1 Internal reference select as non-inverting input to comparator
Note: refer to this chapter introduction to verify if any other config bits are necessary to enable the bandgap
reference in the chip level.
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, ACMPO.
0 Analog comparator output not available on ACMPO
1 Analog comparator output is driven out on ACMPO
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