Z84C2008PEG Zilog, Z84C2008PEG Datasheet - Page 49

• 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

UM008005-0205
MREQ • RD
Adding RAM
A
10
Most computer systems require some external Read/Write memory for data
storage and stack implementation. Figure 18 illustrates how 256 bytes of
static memory are added to the previous example in Figure 17. The
memory space is assumed to be organized as follows:
In this diagram the address space is described in hexadecimal notation.
Address bit A10 separates the ROM space from the RAM space, allowing
this address to be used for the chip select function. For larger amounts of
external ROM or RAM, a simple TTL decoder is required to form the chip
selects.
Figure 18. ROM and RAM Implementation
CE2
CE1
1K x 8
ROM
D
A
7
7
–D
–A
0
0
256 Bytes RAM
1 Kbyte ROM
Hardware and Software Implementation Examples
Address Bus
Data Bus
WR
RD
OD
R/W
256 x 4
Address:
0000H
03FFH
0400H
04FFFH
RAM
D
A
3
7
–D
–A
CE2
0
0
CE1
MRQ
A
10
WR
RD
R/W
OD
User’s Manual
256 x 4
RAM
D
Z80 CPU
A
7
7
–D
–A
CE2
4
CE1
0
A
MRQ
10
29