Table 6.4 I/O Expander Default Output Signal Value - Renesas IDT 89HPES4T4 User Manual

IDT SMBus Interfaces
Notes
PES4T4 User Manual
SMBus I/O
Expander
Bit
(I/O-x.4)
(I/O-x.5)
(I/O-x.6)
(I/O-x.7)

Table 6.4 I/O Expander Default Output Signal Value

The following I/O expander configuration sequence is issued by the PES4T4 to I/O expanders zero and
one (i.e., the ones that contain hot-plug signals).
– Write the default value of the outputs bits on the lower eight I/O expander pins (i.e., I/O-0.0 through
I/O-0.7) to I/O expander register 2.
– Write the default value of the outputs bits on the upper eight I/O expander pins (i.e., I/O-1.0
through I/O-1.7) to I/O expander register 3.
– Write value 0x0 to I/O expander register 4 (no inversion in IO-0)
– Write value 0x0 to I/O expander register 5 (no inversion in IO-1)
– Write the configuration value to select inputs/outputs in the lower eight I/O expander bits (i.e., I/O-
0.0 through I/O-0.7) to I/O expander register 6.
– Write the configuration value to select inputs/outputs in the upper eight I/O expander bits (i.e., I/
O-1.0 through I/O-1.7) to I/O expander register 7.
– Read value of I/O expander register 0 to obtain the current state of the lower eight I/O expander
bits (i.e., I/O-0.0 through I/O-0.7)
– Read value of I/O expander register 1 to obtain the current state of the upper eight I/O expander
bits (i.e., I/O-1.0 through I/O-1.7)
The following I/O expander configuration sequence is issued by the PES4T4 to I/O two (i.e., the one that
contain power good inputs).
– Write the default value of the outputs bits on the lower eight I/O expander pins (i.e., I/O-0.0 through
I/O-0.7) to I/O expander register 2.
– Write value 0x0 to I/O expander register 4 (no inversion in IO-0)
– Write value 0x0 to I/O expander register 5 (no inversion in IO-1)
– Write the configuration value to select inputs/outputs in the lower eight I/O expander bits (i.e., I/O-
0.0 through I/O-0.7) to I/O expander register 6.
– Write the configuration value to select all inputs upper eight I/O expander bits (i.e., I/O-1.0 through
I/O-1.7) to I/O expander register 7.
– Read value of I/O expander register 0 to obtain the current state of the lower eight I/O expander
bits (i.e., I/O-0.0 through I/O-0.7)
– Read value of I/O expander register 1 to obtain the current state of the upper eight I/O expander
bits (i.e., I/O-1.0 through I/O-1.7)
Signal
P2AIN Attention indicator output (off)
P2PIN Power indicator output (on)
P2PEP Power enable output (on)
P2ILOCKP Electromechanical interlock (negated - off)
6 - 6
Defaul
Description
t Value
February 1, 2011
1
0
1
0