IDT SMBus Interfaces
PES16T4AG2 User Manual
5 - 7
May 23, 2013
Notes
The default value of I/O expander outputs is shown in Table 5.4. Note that this default value may be
modified via serial EEPROM or SMBus configuration prior to SMBus initialization by changing the state of
the PCI Express Slot Control Register (PCIESCTL) or Hot-Plug Configuration Control (HPCFGCTL).
The following I/O expander configuration sequence is issued by the PES16T4AG2 to I/O expanders
zero, one and three (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 PES16T4AG2 to I/O two (i.e., the
one that contains 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)
SMBus I/O
Expander
Bit
Signal
Description
Default
Value
(I/O-x.4)
P2AIN
Attention indicator output (off)
1
(I/O-x.5)
P2PIN
Power indicator output (on)
0
(I/O-x.6)
P2PEP
Power enable output (on)
1
(I/O-x.7)
P2ILOCKP
Electromechanical interlock (negated - off)
0
Table 5.4 I/O Expander Default Output Signal Value
Содержание 89HPES16T4AG2
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Страница 14: ...IDT List of Tables PES16T4AG2 User Manual vi May 23 2013 Notes...
Страница 16: ...IDT List of Figures PES16T4AG2 User Manual viii May 23 2013 Notes...
Страница 20: ...IDT Register List PES16T4AG2 User Manual xii May 23 2013 Notes...
Страница 72: ...IDT SMBus Interfaces PES16T4AG2 User Manual 5 20 May 23 2013 Notes...
Страница 76: ...IDT Power Management PES16T4AG2 User Manual 6 4 May 23 2013 Notes...
Страница 156: ...IDT Configuration Registers PES16T4AG2 User Manual 8 74 May 23 2013 Notes...