Z84C2008PEG Zilog, Z84C2008PEG Datasheet - Page 38

• Manufacturer Part Number: Z84C2008PEG
• Description: IC 8MHZ Z80 CMOS PIO 40-DIP
• Manufacturer: Zilog
• Series: Z80r

Specifications of Z84C2008PEG

• Processor Type: Z80
• Features: Low Power CMOS
• Speed: 8MHz
• Voltage: 5V
• Mounting Type: Through Hole
• Package / Case: 40-DIP (0.620", 15.75mm)
• Cpu Speed: 8MHz
• Digital Ic Case Style: DIP
• No. Of Pins: 40
• Supply Voltage Range: 5V
• Operating Temperature Range: -40°C To +100°C
• Svhc: No SVHC (18-Jun-2010)
• Rohs Compliant: Yes
• Processor Series: Z84C2xx
• Core: Z80
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 16
• Operating Supply Voltage: 0 V to 5 V
• Maximum Operating Temperature: + 100 C
• Mounting Style: Through Hole
• Minimum Operating Temperature: - 40 C
• Base Number: 84
• Clock Frequency: 8MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

18
UM008005-0205
Z80 CPU
User’s Manual
HALT Exit
A
15
MREQ
RFSH
— A
CLK
NMI
RD
Figure 10. Non-Maskable Interrupt Request Operation
Whenever a software HALT instruction is executed, the CPU executes
NOPs until an interrupt is received (either a non-maskable or a maskable
interrupt while the interrupt flip-flop is enabled). The two interrupt lines are
sampled with the rising clock edge during each T4 state as depicted in
Figure 11. If a non-maskable interrupt has been received or a maskable
interrupt has been received and the interrupt enable flip-flop is set, then the
HALT state is exited on the next rising clock edge. The following cycle is an
interrupt acknowledge cycle corresponding to the type of interrupt that was
received. If both are received at this time, then the non-maskable one is
acknowledged since it has highest priority. The purpose of executing NOP
instructions while in the HALT state is to keep the memory refresh signals
active. Each cycle in the HALT state is a normal M1 (fetch) cycle except
that the data received from the memory is ignored and a NOP instruction is
forced internally to the CPU. The HALT acknowledge signal is active
during this time indicating that the processor is in the HALT state.
M1
0
Last M Cycle
Last T State
T
1
PC
T
2
M1
T
3
Refresh
T
4
Overview
T
1