Z86C83 Datasheet, PDF (27/46 Pages) Zilog, Inc. – Z8 MCU MICROCONTROLLERS

Z86C83/C84
Z8^® MCU Microcontrollers
FUNCTIONAL DESCRIPTION (Continued)
All Z8 interrupts are vectored through locations in the
program memory. This memory location and the next byte
contain the 16-bit address of the interrupt service routine
for that particular interrupt request. To accommodate
polled interrupt systems, interrupt inputs are masked and
the Interrupt Request register is polled to determine which
of the interrupt requests need service.
An interrupt resulting from AN1 is mapped into IRQ2, and
an interrupt from AN2 is mapped into IRQ0. Interrupts
IRQ2 and IRQ0 may be rising, falling, or both edge
triggered, and are programmable by the user. The
software may poll to identify the state of the pin.
Programming bits for the Interrupt Edge Select is located
in the IRQ Register (R250), bits D7 and D6. The
configuration is shown in Table 11.
Table 11. IRQ Register
IRQ
D7
D6
0
0
0
1
1
0
1
1
Notes:
F = Falling Edge
R = Rising Edge
Interrupt Edge
P31
P32
F
F
F
R
R
F
R/F
R/F
Clock. The Z8 on-chip oscillator has a high-gain, parallel-
resonant amplifier for connection to a crystal, LC, RC,
ceramic resonator, or any suitable external clock source
(XTAL1 = Input, XTAL2 = Output). The crystal should be
AT cut, 16 MHz max., with a series resistance (RS) of less
than or equal to 100 Ohms when clocking from 1 MHz to
16 MHz.
The crystal should be connected across XTAL1 and
XTAL2 using the vendor's recommended capacitor values
from each pin directly to the device Ground pin to reduce
Ground noise injection into the oscillator.
Note: For better noise immunity, the capacitors should be
tied directly to the device Ground pin (V_SS).
C1
VSS* *
C2
VSS* *
XTAL1
C1
VSS* *
XTAL2
C2
VSS* *
XTAL1
L
XTAL2
Ceramic Resonator or
Crystal
C1, C2 = 47 pF TYP *
f = 8 MHz
LC
C1, C2 = 22 pF
L = 130 uH *
f = 3 MHz *
* Preliminary value including pin parasitics
* * Device ground pin
Figure 21. Oscillator Configuration
XTAL1
XTAL2
External Clock
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DS96DZ80203