Z86L04 Zilog., Z86L04 Datasheet - Page 18

• Manufacturer Part Number: Z86L04
• Description: Z8 8-Bit Cost-Effective Microcontrollers
• Manufacturer: Zilog.

FUNCTIONAL DESCRIPTION (Continued)
Z86L04/L08
Z8 8-Bit Cost-Effective Microcontrollers
Interrupts. The Z8 has five interrupts from four different
sources. These interrupts are maskable and prioritized
(Figure 15). The sources are divided as follows: the falling
edge of P31 (AN1), P32 (AN2), P33 (REF), the rising edge
of P32 (AN2), and one counter/timer. The Interrupt Mask
Register globally or individually enables or disables the
five interrupt requests (Table 4).
When more than one interrupt is pending, priorities are re-
solved by a programmable priority encoder that is con-
trolled by the Interrupt Priority register. All Z8 interrupts are
vectored through locations in program memory. When an
Interrupt machine cycle is activated, an Interrupt Request
is granted. This disables all subsequent interrupts, saves
the Program Counter and Status Flags, and then branches
to the program memory vector location reserved for that in-
terrupt. This memory location and the next byte contain the
16-bit starting 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 needs service.
18
Interrupt
Request
Interrupt
Enable
Global
Figure 15. Interrupt Block Diagram
P R E L I M I N A R Y
Vector Select
User must select any Z86E08 mode in Zilog's C12 ICE-
BOX™ emulator. The rising edge interrupt is not directly
supported on the Z86CCP00ZEM emulator.
IRQ0
IRQ1
IRQ2
IRQ3
IRQ4
IRQ5
Note:
F = Falling edge triggered
R = Rising edge triggered
IRQ0 - IRQ5
Name
Priority
Logic
IMR
IRQ
IPR
Table 4. Interrupt Types, Sources, and Vectors
AN2(P32)
REF(P33)
AN1(P31)
AN2(P32)
T0
T1
Source
Location
Vector
10,11
6
0,1
2,3
4,5
6,7
8,9
External (F)Edge
External (F)Edge
External (F)Edge
External (R)Edge
Internal
Internal
Comments
DS97LVO0901
Zilog