MC9S08DZ128 Datasheet, PDF (199/458 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 9
5-V Analog Comparator (S08ACMPV3)
9.1 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).
All MC9S08DZ128 Series MCUs have two full function ACMPs. MCUs in the 48-pin package have two
ACMPs, but the output of ACMP2 is not accessible.
NOTE
MC9S08DZ128 Series devices operate at a higher voltage range (2.7 V to
5.5 V) and do not include stop1 mode. Please ignore references to stop1.
ACMP2O is not available in the 48-pin package.
9.1.1 ACMP Configuration Information
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 5.8.7, “System Power Management Status and Control 1
Register (SPMSC1).” For value of bandgap voltage reference see Appendix A, “Electrical Characteristics”
MC9S08DZ128 Series Data Sheet, Rev. 1
Freescale Semiconductor
199