Avago Technologies LSI8751D User Manual

Page 178

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5-62

SCSI Operating Registers

Wide Residue message is received. It may also be an
overrun data byte. The power-up value of this register is
indeterminate.

Register: 0x46 (0xC6)

Memory Access Control (MACNTL)
Read/Write

TYP[3:0]

Chip Type

[7:4]

These bits identify the chip type for software purposes.
This technical manual applies to devices that have these
bits set to 0x07.

Bits 3 through 0 of this register are used to determine if
an external bus master access is to local or far memory.
When bits 3 through 0 are set, the corresponding access
is considered local and the MAC/_TESTOUT pin is driven
high. When these bits are clear, the corresponding
access is to far memory and the MAC/_TESTOUT pin is
driven low. This function is enabled after a Transfer
Control SCRIPTS instruction is executed.

DWR

DataWR

3

This bit is used to define if a data write is considered to
be a local memory access.

DRD

DataRD

2

This bit is used to define if a data read is considered to
be a local memory access.

PSCPT

Pointer SCRIPTS

1

This bit is used to define if a pointer to a SCRIPTS
indirect or table indirect fetch is considered to be a local
memory access.

SCPTS

SCRIPTS

0

This bit is used to define if a SCRIPTS fetch is
considered to be a local memory access.

7

4

3

2

1

0

TYP

DWR

DRD

PSCPT

SCPTS

1

1

1

1

0

0

0

0

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