Z16M1720ASG1868 Zilog, Z16M1720ASG1868 Datasheet - Page 67

• Manufacturer Part Number: Z16M1720ASG1868
• Description: IC PCMCIA INTERFACE 100-VQFP
• Manufacturer: Zilog

Specifications of Z16M1720ASG1868

• Applications: *
• Interface: *
• Voltage - Supply: *
• Package / Case: 100-LQFP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

UM008101-0601
1. Transfer Memory-to-I/O (optional search)
2. Transfer I/O-to-Memory (optional search)
3. Transfer Memory-to-Memory (optional search)
4. Transfer I/O-to-I/O (optional search)
5. Search Memory
6. Search I/O
Modes of Operation
Figure 19.
Within any class of operation, the Z80 DMA can be programmed to operate
in one of three Transfer and/or, Search modes:
Byte Mode
Data operations are performed one byte at a time. Between each byte oper-
ation the system bus is released to the CPU. The bus is requested again for
each succeeding byte operation. This is also sometimes called Single mode
or byte-at-a-time mode.
Burst Mode
Data operations continue until a port’s Ready line to the DMA goes
inactive. The DMA then stops (releases the system bus) after completing its
current byte operation. This is also called demand mode.
Continuous Mode
Data operations continue until the end of the programmed block of data or a
stop-on-match condition is reached before the system bus is released. If a
Basic Functions of the Z80 DMA
Memory
5
3
DMA
1
2
6
4
<   % 2 7 2 G T K R J G T C N U
Direct Memory Access
7 U G T / C P W C N
I/O
I/O