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ITA-1611 User Manual
Chapter 6
G
PIO Programming
Guide
PCA9554 register 3:
This register configures directions of I/O pins. If value of a certain bit of this register
is set, pin of corresponding port will be defined as inputs with high impedance output
driver. If the value is cleared, then the port will be defined as outputs. When reset, ini-
tial definition of I/O will be inputs with weak pull-up to VDD.
Register 3 is used to set
GPIO
to I
nput
or
Output
:
If the corresponding bit is ‘0’, then GPIO pin is enabled as Output;
If the corresponding bit is ‘1?then GPIO pin is enabled as Input.
Examples:
Take ITA-1610 as example,. Suppose GPIO 00 is set to Output, GPIO 07 is set to
Input, both pins are connected, then how to set the corresponding registers?
GPIO 00 corresponds to PCA9554 0x40 IO0, while GPIO 07 corresponds to
PCA9554 0x40 IO7.
Set GPIO 00 to Output:
1.
Read value of SMBUS slave 0x40 register 3 byte,
2.
Set bit 0 the value read in step 1 to 0 and write it to SMBUS slave 0x40 register
3,
3.
Read value of SMBUS slave 0x40 register 1 byte,
4.
Depending on the output value is Low or High, set bit 0 the value read in step 3
to 0 or 1 and write it to SMBUS slave 0x40 register 1.
Set G
PIO 07
to
Input
value:
1.
Read value of SMBUS slave 0x40 register 3 byte,
2.
Set bit 7 the value read in step 1 to 1 and write it to
SMBUS slave 0x40 register
3
,
3.
Read value of
SMBUS slave 0x40 register 0 byte
,
Determine Input value to be Low or High according to value of
step 3 bit7
.
Summary of Contents for ITA-1611 Series
Page 1: ...User Manual ITA 1611 Series Fanless Embedded Celeron Dual Core Compact Industrial Computer...
Page 11: ...Chapter 1 1 Overview This chapter provides general Information about the ITA 1611...
Page 15: ...Chapter 2 2 H W Installation This chapter provides H W Instal lation about the ITA 1611...
Page 27: ...Chapter 3 3 System Setup This chapter introduces the instal lation process of ITA 1611...
Page 33: ...Chapter 4 4 AMI BIOS This chapter introduces how to configure AMI BIOS...
Page 52: ...ITA 1611 User Manual 42...
Page 53: ...Chapter 5 5 Driver Installation This chapter describes how to Install drivers...
Page 57: ...Chapter 6 6 GPIO Programming Guide This chapter introduces GPIO pro gramming guide...
Page 66: ...ITA 1611 User Manual 56...