MC9S08SH8CSCR View Datasheet(PDF) - Freescale Semiconductor
Part Name
Description
MFG CO.
'MC9S08SH8CSCR' PDF : 341 Pages View PDF
Chapter 8
Analog Comparator 5-V (S08ACMPV2)
8.1 Introduction
The analog comparator module (ACMP) provides a circuit for comparing two analog input voltages or for
comparing one analog input voltage to an internal reference voltage. The comparator circuit is designed to
operate across the full range of the supply voltage (rail-to-rail operation).
Figure 8-1 shows the MC9S08SH8 block diagram with the ACMP highlighted.
8.1.1 ACMP Configuration In ormation
When using the bandgap reference voltage for input to ACMP+, the user must enable the bandgap buffer
by setting BGBE =1 in SPMSC1 see Section 5.7.7, “System Power Management Status and Control 1
Register (SPMSC1)”. For value of bandgap voltage reference see Section A.6, “DC Characteristics”.
8.1.2 ACMP in Stop3 Mode
S08ACMPV2 continues to operate in stop3 mode if enabled. If ACOPE is enabled, comparator output will
operate as in the normal operating mode and will control ACMPO pin. The MCU is brought out of stop
when a compare event occurs and ACIE is enabled; ACF flag sets accordingly.
8.1.3 ACMP/TPM Configuration In ormation
The ACMP module can be configured to connect the output of the analog comparator to TPM1 input
capture channel 0 by setting ACIC in SOPT2. With ACIC set, the TPM1CH0 pin is not available externally
regardless of the configuration of the TPM1 module for channel 0.
MC9S08SH8 MCU Series Data Sheet, Rev. 3
Freescale Semiconductor
113
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