LAN91C110 Ver la hoja de datos (PDF) - SMSC -> Microchip

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LAN91C110

FEAST Fast Ethernet Controller for PCMCIA and Generic 16-Bit Applications

SMSC -> Microchip 

BANK 0

OFFSET

A

NAME

MEMORY CONFIGURATION

REGISTER

TYPE

Lower Byte -

READ/WRITE

Upper Byte -

READ ONLY

SYMBOL

MCR

HIGH

BYTE

0

LOW

BYTE

0

MEMORY SIZE MULTIPLIER

0

1

1

0

1

0

1

MEMORY RESERVED FOR TRANSMIT (IN BYTES * 256 * M)

0

0

0

0

0

0

0

MEMORY RESERVED FOR TRANSMIT - Programming this value allows the host CPU to reserve memory to be used

later for transmit, limiting the amount of memory that receive packets can use. When programmed for zero, the memory

allocation between transmit and receive is completely dynamic. When programmed for a non-zero value, the allocation is

dynamic if the free memory exceeds the programmed value, while receive allocation requests are denied if the free

memory is less or equal to the programmed value. This register defaults to zero upon reset. It is not affected by the

RESET MMU command.

The value written to the MCR is a reserved memory space IN ADDITION TO ANY MEMORY CURRENTLY IN USE. If the

memory allocated for transmit plus the reserved space for transmit is required to be constant (rather than grow with

transmit allocations) the CPU should update the value of this register after allocating or releasing memory.

The contents of the MIR as well as the low byte of the MCR are specified in units of 256 * M bytes, where M is the

Memory Size Multiplier. M=2 for the LAN91C110. A value of 04h in the lower byte of the MCR is equal to one 2K page (4

* 256 *2 = 2K); since memory must be reserved in multiples of pages, bits 0 and 1 of the MCR should be written to 1 only

when the entire memory is being reserved for transmit (i.e., low byte of MCR = FFh).

BANK1

OFFSET

0

NAME

CONFIGURATION REGISTER

TYPE

READ/WRITE

SYMBOL

CR

The Configuration Register holds bits that define the adapter configuration and are not expected to change during run-

time. This register is part of the EEPROM saved setup.

HIGH

BYTE

MII

Reserved

SELECT

NO WAIT Reserved

FULL

STEP

Reserved

AUI

SELECT

1

0

1

0

0

0

0

0

LOW

BYTE

1

Reserved

Reserved

INT SEL1 INT SEL0

1

0

1

1

0

0

0

1

SMSC LAN91C110 Rev. B

Page 23

DATASHEET

Revision 1.0 (11-04-08)

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