Z0847006PSG Zilog, Z0847006PSG Datasheet - Page 54

• Manufacturer Part Number: Z0847006PSG
• Description: IC 6MHZ Z80 NMOS DART 40-DIP
• Manufacturer: Zilog
• Series: Z80r

Specifications of Z0847006PSG

• Processor Type: Z80
• Features: Dual Channel Asynchronous Receiver/Transmitter (DART)
• Speed: 6MHz
• Voltage: 5V
• Mounting Type: Through Hole
• Package / Case: 40-DIP (0.620", 15.75mm)
• Mounting Style: Through Hole
• Cpu Speed: 6MHz
• Digital Ic Case Style: DIP
• No. Of Pins: 40
• Supply Voltage Range: 5V
• Operating Temperature Range: 0°C To +70°C
• Svhc: No SVHC (18-Jun-2010)
• Base Number: 847006
• Rohs Compliant: Yes
• Clock Frequency: 6MHz
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

UM008101-0601
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7 U G T / C P W C N
DMACs are used when one or more of the following situations or require-
ments are present:
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Small and low-performance systems generally run without DMA.
Medium-performance systems can also be designed without DMA if the
CPU can handle transfers fast enough and still perform other operations.
When systems require fast transfers or fast response, DMACs are strong
candidates for performance enhancement. Not only do DMACs transfer
faster than most CPUs, but the response time is better. Response times can
even be improved using the techniques described above for CPU response.
The following examples are cases in which DMA is usually the best choice:
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The trade-off for speed is that the CPU typically remains idle and lacks full
or partial control of the system bus while the DMA is operating. This
condition can affect total system throughput, and can also affect such things
as memory refresh and other interrupts.
CPU has too much I/O and cannot perform other tasks properly
Data transfer must be faster than the CPU can perform
Transfer response tune (startup) must be faster than the CPU can provide
Disk and diskette controllers
Scanning operations, such as CRT I/O
Data acquisition
Memory-to-memory transfers
Memory searches
Backup storage (I/O-to-I/O)
Parallel bus systems such as the IEEE 488
Fiber optic links
Block transfers in networking, multiprocessing, or multiprogramming
Direct Memory Access