General Purposed Io - MSI MS-98J4 User Manual

GPIO WDT BKL Programming

General Purposed IO

1. General Purposed IO – GPIO/DIO
The GPIO port configuration addresses are listed in the following table:
Name
N_GPI0
N_GPI1
N_GPI2
N_GPI3
Note: GPIO should be accessed through controller device 0x9C on SMBus. The associated access
method in examples (SMBus_ReadByte, SMBus_WriteByte) are provided in part 4.
1.1 Set output value of GPO
1. Read the value from GPO port.
2. Set the value of GPO address.
3. Write the value back to GPO port.
Example: Set N_GPO0 output "high"
val =SMBus_ReadByte (0x9C, 0x21);
val = val | (1<<0);
SMBus_WriteByte (0x9C, 0x21, val);
Example: Set N_GPO1 output "low"
val = SMBus_ReadByte (0x9C, 0x21);
val = val & (~(1<<1));
SMBus_WriteByte (0x9C, 0x21, val);
1.2 Read input value from GPI:
1. Read the value from GPI port.
2. Get the value of GPI address.
Example: Get N_GPI2 input value.
val = SMBus_ReadByte (0x9C, 0x22); // Read value from N_GPI2 port through SMBus.
val = val & (1<<6);
if (val) printf ("Input of N_GPI2 is High");
else
Example: Get N_GPI6 input value.
val = SMBus_ReadByte (0x9C, 0x22);
val = val & (1<<7);
if (val) printf ("Input of N_GPI3 is High");
else
A-4
IO Port IO address
0x22 Bit 4
0x22 Bit 5
0x22 Bit 6
0x22 Bit 7
printf ("Input of N_GPI2 is Low");
printf ("Input of N_GPI3 is Low");
Name IO Port
N_GPO0 0x21
N_GPO1 0x21
N_GPO2 0x21
N_GPO3 0x21
// Read value from N_GPO0 port through SMBus.
// Set N_GPO0address (bit 0) to 1 (output "high").
// Write back to N_GPO0 port through SMBus.
// Read value from N_GPO1 port through SMBus..
// Set N_GPO1 address (bit 1) to 0 (output "low").
// Write back to N_GPO1 port through SMBus.
// Read N_GPI2 address (bit 6).
// Read value from N_GPI3 port through SMBus.
// Read N_GPI6 address (bit 7).
IO address
Bit 0
Bit 1
Bit 2
Bit 3