Register: 0x07 – Avago Technologies LSI53C876E User Manual
Page 131
SCSI Registers
4-37
SCRIPTS Select or Reselect instruction. The value
written is the binary-encoded ID. The priority of the
16 possible IDs, in descending order, is:
Register: 0x07
General Purpose (GPREG)
Read/Write
The general purpose register drives and senses values on the general
purpose I/O pins. If both SCSI function GPREG registers define a single
GPIO pin as an output, the results are indeterminate.
R
Reserved
[7:5]
GPIO[4:0]
General Purpose I/O
[4:0]
These bits are programmed through the
register as inputs, outputs, or to
perform special functions. As an output, these pins
enable or disable external terminators. It is also possible
to program these signals as live inputs and sense them
through a SCRIPTS register to register Move Instruction.
GPIO[2:0] default as inputs and GPIO4 defaults as an
output pin. When configured as inputs, an internal pull-up
is enabled.
It is possible to use GPIO4 to enable or disable V
PP
, the
12 V power supply to the external flash memory. This bit
powers up with the power to the external memory
disabled.
The LSI Logic PCI to SCSI host adapters use the GPIO4
pin in the process of flashing a new SDMS ROM.
Highest
Lowest
7
6
5
4
3
2
1
0
15 14 13 12 11
0
9
8
7
5
4
0
R
GPIO[4:0]
x
x
x
0
x
x
x
x