Z0847006PSG Zilog, Z0847006PSG Datasheet - Page 178

• 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
<   % 2 7 2 G T K R J G T C N U
7 U G T / C P W C N
BUSREQ
Note: RDY is detected as a level, not an edge
Figure 65.
Continuous mode is the only instance when a pulse on RDY allows the
DMA to become bus master.In this event, the DMA becomes bus master
but does not begin operations.
When the DMA detects a Low on BAI for two consecutive rising edges of
CLK, the DMA begins transferring data on the next rising edge of CLK.
In Byte mode, after each byte is transferred, the DMA waits until its BAI
line goes inactive before requesting the bus again on BUSREQ for the next
byte transfer. This feature allows a minimum of one CPU machine cycle to
occur between each byte transferred.
Bus Release Byte-at-a-Time
In Byte mode, BUSREQ is brought High on the rising edge of CLK prior to
the end of each read cycle (search-only) or write cycle (transfer and trans-
fer/search) as illustrated in Figure 66. This action occurs regardless of the
state of RDY. There is no possibility of confusion when a Z80 CPU is used
because the CPU cannot begin an operation until the following clock cycle.
Nor does this condition affect most other CPUs. The result of timing is one-
clock-cycle less time needed for a byte transfer.
RDY
CLK
BAI
Inactive
Active
Bus Request and Acceptance Timing
Inactive
DMA
Direct Memory Access
Active
DMA