DP83901AV National Semiconductor, DP83901AV Datasheet - Page 37

• Manufacturer Part Number: DP83901AV
• Description: IC CONTROLLR SER NETWK IN 68PLCC
• Manufacturer: National Semiconductor

Specifications of DP83901AV

• Controller Type: Serial Network Interface Controller
• Interface: Serial
• Voltage - Supply: 5V
• Current - Supply: 110mA
• Mounting Type: Surface Mount
• Package / Case: 68-LCC (J-Lead)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Operating Temperature: -
• Other names: *DP83901AV

13 0 Bus Arbitration and Timing
The SNIC operates in three possible modes
Upon power-up the SNIC is in an indeterminate state After
receiving a hardware reset the SNIC is a bus slave in the
Reset State the receiver and transmitter are both disabled
in this state The reset state can be re-entered under three
conditions soft reset (Stop Command) hard reset (RESET
input) or an error that shuts down the receiver of transmitter
(FIFO underflow or overflow) After initialization of registers
the SNIC is issued a Start command and the SNIC enters
Idle state Until the DMA is required the SNIC remains in idle
state The idle state is exited by a request from the FIFO on
the case of receiver or transmit or from the Remote DMA in
the case of Remote DMA operation
BUS MASTER (WHILE PERFORMING DMA)
BUS SLAVE (WHILE BEING ACCESSED BY CPU)
IDLE
After acquiring
16-Bit Address 8-Bit Data
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the bus in a BREQ BACK handshake the Remote or Local
DMA transfer is completed and the SNIC re-enters the idle
state
DMA TRANSFERS TIMING
The DMA can be programmed for the following types of
transfers
All DMA transfers use BSCK for timing 16-Bit Address
modes require 4 BSCK cycles as shown below
16-Bit Address 8-bit Data Transfer
16-Bit Address 16-bit Data Transfer
32-Bit Address 8-bit Data Transfer
32-Bit Address 16-bit Data Transfer
TL F 10469 – 20
TL F 10469– 21