Z86C02 Datasheet, PDF (18/37 Pages) Zilog, Inc. – Two On-Board Comparators

Z86C02/E02/L02
Cost Effective, 512-Byte ROM CMOS Z8^® Microcontrollers
Zilog
PIN FUNCTIONS (Continued)
Port 3, P33-P31. Port 3 is a 3-bit, CMOS compatible port
with three fixed input (P33-P31) lines. These three input
lines can be configured under software control as digital
Schmitt-trigger inputs or analog inputs.
These three input lines are also used as the interrupt
sources IRQ0-IRQ3 and as the timer input signal T_IN (Fig-
ure 10).
Z8
Port 3
0 = Digital
R247 = P3M 1 = Analog
D1
DIG.
PAD
+
P31 (AN1)
AN.
-
PAD
P32 (AN2)
+
PAD
-
P33 (REF)
TIN
P31 Data Latch
IRQ2
IRQ3
P32 Data Latch
IRQ0
P33 Data Latch
V_cc
IRQ1
IRQ 0,1,2 = Falling Edge Detection
IRQ3 = Rising Edge Detection
Figure 10. Port 3 Configuration
Comparator Inputs. Two analog comparators are added
to input of Port 3, P31 and P32, for interface flexibility. The
comparators reference voltage P33 (REF) is common to
both comparators.
Typical applications for the on-board comparators; Zero
crossing detection, A/D conversion, voltage scaling, and
threshold detection. In analog mode, P33 input functions
serve as a reference voltage to the comparators.
The dual comparator (common inverting terminal) features
a single power supply which discontinues power in STOP
mode. The common voltage range is 0-4 V when the V_CC
is 5.0 V; the power supply and common mode rejection ra-
tios are 90 dB and 60 dB, respectively.
Interrupts are generated on either edge of Comparator 2's
output, or on the falling edge of Comparator 1's output.
The comparator output is used for interrupt generation,
Port 3 data inputs, or T_IN through P31. Alternatively, the
comparators can be disabled, freeing the reference input
(P33) for use as IRQ1 and/or P33 input.
18
PRELIMINARY
DS96DZ80301