Philips 8-bit microcontroller with two-clock 80C51 core UM10109 Manual De Usuario
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
User manual
Rev. 02 — 23 May 2005
96 of 133
Philips Semiconductors
UM10109
P89LPC932A1 User manual
13.6 Comparators configuration example
The code shown below is an example of initializing one comparator. Comparator 1 is
configured to use the CIN1A and CMPREF inputs, outputs the comparator result to the
CMP1 pin, and generates an interrupt when the comparator output changes.
configured to use the CIN1A and CMPREF inputs, outputs the comparator result to the
CMP1 pin, and generates an interrupt when the comparator output changes.
CMPINIT:
MOV PT0AD,#030h
;Disable digital INPUTS on CIN1A, CMPREF.
ANL P0M2,#0CFh
;Disable digital OUTPUTS on pins that are used
ORL P0M1,#030h
;for analog functions: CIN1A, CMPREF.
MOV CMP1,#024h
;Turn on comparator 1 and set up for:
;Positive input on CIN1A.
;Negative input from CMPREF pin.
;Output to CMP1 pin enabled.
CALL delay10us
;The comparator needs at least 10 microseconds before use.
ANL CMP1,#0FEh
;Clear comparator 1 interrupt flag.
SETB EC
;Enable the comparator interrupt,
SETB EA
;Enable the interrupt system (if needed).
RET
;Return to caller.
The interrupt routine used for the comparator must clear the interrupt flag (CMF1 in this
case) before returning
case) before returning
a. CPn, CNn, OEn = 0 0 0
b. CPn, CNn, OEn = 0 0 1
c. CPn, CNn, OEn = 0 1 0
d. CPn, CNn, OEn = 0 1 1
e. CPn, CNn, OEn = 1 0 0
f. CPn, CNn, OEn = 1 0 1
g. CPn, CNn, OEn = 1 1 0
h. CPn, CNn, OEn = 1 1 1
Fig 46. Comparator configurations.
CINnA
CMPREF
002aaa618
COn
CINnA
CMPREF
002aaa620
COn
CMPn
CINnA
V
REF
(1.23 V)
002aaa621
COn
CINnA
V
REF
(1.23 V)
002aaa622
COn
CMPn
CINnB
CMPREF
002aaa623
COn
CINnB
CMPREF
002aaa624
COn
CMPn
CINnB
V
REF
(1.23V)
002aaa625
COn
CINnB
V
REF
(1.23 V)
002aaa626
COn
CMPn