Z84C9008VSG Zilog, Z84C9008VSG Datasheet - Page 31

• Manufacturer Part Number: Z84C9008VSG
• Description: IC 8MHZ Z80 KIO 84-PLCC
• Manufacturer: Zilog
• Series: Z80r

Specifications of Z84C9008VSG

• Processor Type: Z80
• Features: Serial/Parallel Input/Output, Counter/Timer Circuit
• Speed: 8MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 84-LCC (J-Lead)
• Maximum Operating Temperature: + 70 C
• Minimum Operating Temperature: 0 C
• Mounting Style: SMD/SMT
• Cpu Speed: 8MHz
• Digital Ic Case Style: LCC
• No. Of Pins: 84
• Supply Voltage Range: 5V
• Operating Temperature Range: 0°C To +70°C
• Svhc: No SVHC (18-Jun-2010)
• Rohs Compliant: Yes
• Base Number: 84
• Clock Frequency: 8MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

TIMING
UM008005-0205
Overview
The Z80 CPU executes instructions by stepping through a precise set of
basic operations. These include:
•
•
•
All instructions are series of basic operations. Each of these operations can
take from three to six clock periods to complete or they can be lengthened to
synchronize the CPU to the speed of external devices. The clock periods are
referred to as T (time) cycles and the operations are referred to as M
(machine) cycles. Figure 4 illustrates how a typical instruction is series of
specific M and T cycles. Notice that this instruction consists of three
machine cycles (M1, M2, and M3). The first machine cycle of any
instruction is a fetch cycle which is four, five, or six T cycles long (unless
lengthened by the WAIT signal, which is described in the next section). The
fetch cycle (M1) is used to fetch the opcode of the next instruction to be
executed. Subsequent machine cycles move data between the CPU and
memory or I/O devices, and they may have anywhere from three to five T
cycles (again, they may be lengthened by wait states to synchronize the
external devices to the CPU). The following paragraphs describe the timing
which occurs within any of the basic machine cycles.
During T2 and every subsequent Tw, the CPU samples the WAIT line with
the falling edge of Clock. If the WAIT line is active at this time, another
WAIT state is entered during the following cycle. Using this technique, the
read can be lengthened to match the access time of any type of memory
device.
Memory Read or Write
I/O Device Read or Write
Interrupt Acknowledge
User’s Manual
Z80 CPU
Overview
11