Embedded Network Interface (ENI)

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Embedded Network Interface (ENI)
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What is ENI?

• Embedded Network Interface
• Originally called DPO (Digital Product Option)
  card
• Printer without network capability into interface
  with our network card
• Enable an external device with a processor to
  interface the NETARM
• The interface is used as a bridge to the LAN

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More About ENI

• Allows sharing of NETARMs memory system
• Useful for dual processor system
• Second Processor must push / pull data
• NETARM is a slave in ENI mode
• Can use either FIFO mode or Shared Ram mode
• FIFO is fast, but have less control over data
• Shared RAM is slower, but have more control
• ENI must become BUS Master to use Shared RAM
• ENI is muxed with Parallel Ports (one or the
  other)

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Hardware Concept
NetARM (Slave) host
External uP System
(Master) client
ENI Port
Data Addr Bus
Data Addr Bus
RAM
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ENI Hardware
External Device
ENI bi-directional data bus
NETARM
ENI Hardware Peripheral
Transmit FIFO
Receive FIFO
Shared RAM
RAM
DMA Hardware Module
Channel 4
Channel 3
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New GPIO ports on NET50

• ENI module in GPIO mode provides four 8-bit GPIO
  ports
• Two ports are I/O ports (Port D and Port F) and
  two ports are input ports (Port G and Port H)
• GPIO port pins are individually configurable to
  input, output, active high interrupt or active
  low interrupt
• Interrupts are level sensitive

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GPIO Port Interrupts on NET50

• Port D uses interrupt 21 (ENI port 1)
• Port F uses interrupt 20 (ENI port 2)
• Port G uses interrupt 19 (ENI port 3)
• Port H uses interrupt 18 (ENI port 4)

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Modes of Operation

• ENI Shared RAM 16 bit interface
• ENI Shared RAM 8 bit interface
• ENI FIFO 16 interface with 8K Shared memory
• ENI FIFO 8 interface with 8K Shared memory

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Shared RAM Mode

• Allow external device (client) to random access
  external memory which is controlled by the the
  NETARM (host)
• 8/16-bit interface
• Size of Shared RAM is can be one of the following
• 4K, 8K, 16. 32, or 64K
• Location of RAM must be a multiple of the size
  selected
• E.g. ram size of 8k must on located on a 8k
  boundary

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FIFO Mode

• Data-streaming interface between the NETARM and
  the external device
• 8/16-bit interface
• Two 32-byte FIFOs used to transmit and receive
  data
• DMA 3 is used to transfer receive data from FIFO
  to external memory
• DMA 4 is used to transfer transmit data from
  external memory to FIFO
• DMA buffers must start and end on a 32-bit
  boundary
• Data must be padded to conform to buffer
  requirement
• 8K of shared memory can be accessed