NS7520B-1-C36 Digi International, NS7520B-1-C36 Datasheet - Page 56

• Manufacturer Part Number: NS7520B-1-C36
• Description: IC ARM MICROPROCESSOR 177BGA
• Manufacturer: Digi International
• Series: NET+ARM®r

Specifications of NS7520B-1-C36

• Applications: Network Processor
• Core Processor: ARM7
• Program Memory Type: External Program Memory
• Controller Series: -
• Ram Size: External
• Interface: EBI/EMI, Ethernet, DMA, SPI, UART
• Number Of I /o: 16
• Voltage - Supply: 1.4 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 177-LFBGA
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4 4
B B u s m a s t e r s a n d s l a v e s
BBus masters and slaves
Cycles and BBus arbitration
The BBus module consists of bus master and bus slave modules. The BBus state
machine allows each bus master to control the bus in a round-robin manner. If a bus
master does not require the bus resources when its turn comes around, that bus is
skipped until the next round-robin slot. Each potential bus master presents the BBus
with request and attribute signals. Once mastership is granted, the targeted device is
selected.
Table 19 illustrates bus master and slave modules.
Table 19: BBus masters and slaves
During a normal cycle, each bus master cycle is allowed only one read/write cycle if
another bus master is waiting. There are two exceptions to this rule: burst
transactions and read-modify-write transactions.
In a burst transaction, the master can perform more than one read or write cycle. In
a read-modify-write transaction, the bus master performs one read and write cycle to
the same location.
CPU module
BUS module
EFE module
DMA module
GEN module
MEM module
SER module
Module
N S 7 5 2 0 H a r d w a r e R e f e r e n c e , R e v G 9 / 2 0 0 7
Y
Y
Y
Master
Y
Y
Y
Y
Y
Y
Y
Slave