Z86E30 Datasheet, PDF (41/66 Pages) Zilog, Inc. – Z8 4K OTP Microcontroller

Zilog
Z86E30/E31/E40
Z8 4K OTP Microcontroller
When more than one interrupt is pending, priorities are re- Programming bits for the Interrupt Edge Select are located
solved by a programmable priority encoder that is con- in bits D7 and D6 of the IRQ Register (R250). The config-
trolled by the Interrupt Priority Register (IPR). An interrupt uration is shown in Table 11.
machine cycle is activated when an interrupt request is
1
granted. Thus, disabling all subsequent interrupts, saves
Table 11. IRQ Register Configuration
the Program Counter and Status Flags, and then branches
to the program memory vector location reserved for that in-
IRQ
Interrupt Edge
terrupt. All interrupts are vectored through locations in the
D7
program memory. This memory location and the next byte
0
contain the 16-bit starting address of the interrupt service
routine for that particular interrupt request.
0
1
D6
P31
P32
0
F
F
1
F
R
0
R
F
To accommodate polled interrupt systems, interrupt inputs
1
1
are masked and the interrupt request register is polled to
determine which of the interrupt requests need service.
Notes:
F = Falling Edge
R/F
R/F
R = Rising Edge
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 trig-
gered, and are programmable by the user. The software
may poll to identify the state of the pin.
Clock. The on-chip oscillator has a high-gain, parallel-res-
onant amplifier for connection to a crystal, RC, ceramic
resonator, or any suitable external clock source (XTAL1 =
Input, XTAL2 = Output). The crystal should be AT cut, 10
KHz to 16 MHz max, with a series resistance (RS) less
than or equal to 100 Ohms.
The crystal should be connected across XTAL1 and
XTAL2 using the vendor's recommended capacitor values
from each pin directly to device pin Ground. The RC oscil-
lator option can be selected in the programming mode.
The RC oscillator configuration must be an external resis-
tor connected from XTAL1 to XTAL2, with a frequency-set-
ting capacitor from XTAL1 to Ground (Figure 29).
XTAL1
XTAL1
XTAL1
XTAL1
C1
C1
C1
L
R
XTAL2
XTAL2
C2
C2
XTAL2
XTAL2
Ceramic Resonator or
Crystal
C1, C2 = 47 pF TYP *
F = 8 MHz
LC
C1, C2 = 22 pF
L = 130 µH *
F = 3 MHz *
* Typical value including pin parasitics
RC
@ 5V Vcc (TYP)
C1 = 100 pF
R = 2K
F = 6 MHz
Figure 29. Oscillator Configuration
External Clock
DS97Z8X0500
PRELIMINARY
41