Z86D990 Datasheet, PDF (35/102 Pages) Zilog, Inc. – Low-Voltage Micro controllers with ADC

Z86D990/Z86D991 OTP and Z86L99X ROM
Low-Voltage Microcontrollers with ADC
28
Peripherals
Analog Comparators
The Z86D99/Z86L99 family includes two independent on-chip general-purpose
analog comparators as shown in Figure 13. The comparators are multiplexed with
a digital input signal by the P456CON register. They can also be used to generate
interrupts IRQ0 and IRQ2. The comparators are turned off in STOP mode.
P51
(CIN1)
P50
(CREF1)
+
–
Comparator 1
IRQ2, P51 Data Latch
P456CON
Bit5 1 = comparator
0 = digital
P52
(CIN2)
P53
(CREF2)
+
–
Comparator 2
Figure 13. Analog Comparators
P456CON
Bit4 1 = comparator
0 = digital
IRQ0, P52 Data Latch
Analog/Digital Converter (ADC)
The Z86D99/Z86L99 family incorporates an 8-bit ADC that uses a sigma delta
architecture (Figure 14) comprised of a modulator and a digital filter. The input is
selected (bit 3,2 from ADCCTRL) with an analog mux from 4 (P47–P44) pins that
can be configured as analog inputs (bit 7–4 from ADCCTRL).
Note: Whenever an input pin has an analog value, the digital input
buffer has to be disabled in order to reduce the current through
the device.
PS003807-1002
PRELIMINARY