I/O SPACE - BANK2

 

 

 

 

 

 

 

OFFSET

 

NAME

 

 

TYPE

 

SYMBOL

2

PACKET NUMBER REGISTER

 

READ/WRITE

 

PNR

 

 

 

 

 

 

 

 

 

 

 

PACKET NUMBER AT TX AREA

 

 

 

 

 

 

 

 

 

0

0

0

 

0

0

0

0

0

 

 

 

 

 

 

 

 

 

PACKET NUMBER AT TX AREA - The value written into this register determines which packet number is accessible through the TX area. Some MMU commands use the number stored in this

register as the packet number parameter. This register is cleared by a RESET or a RESET MMU Command.

OFFSET

NAME

TYPE

SYMBOL

3

ALLOCATION RESULT REGISTER

READ ONLY

ARR

This register is updated upon an ALLOCATE MEMORY MMU command.

FAILED

 

 

 

ALLOCATED PACKET NUMBER

 

 

 

 

 

 

 

 

 

1

0

0

0

0

0

0

0

 

 

 

 

 

 

 

 

FAILED - A zero indicates a successful allocation completion. If the allocation fails the bit is set and only cleared when the pending allocation is satisfied. Defaults high upon reset and reset MMU command. For polling purposes, the ALLOC_INT in the Interrupt Status Register should be used because it is synchronized to the read operation. Sequence:

1)Allocate Command

2)Poll ALLOC_INT bit until set

3)Read Allocation Result Register

ALLOCATED PACKET NUMBER - Packet number associated with the last memory allocation request. The value is only valid if the FAILED bit is clear.

NOTE: For software compatibility with future versions, the value read from the ARR after an allocation request is intended to be written into the PNR as is, without masking higher bits (provided FAILED = 0).

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Image 58
SMC Networks SMC91C95 manual This register is updated upon an Allocate Memory MMU command, Failed Allocated Packet Number