LM940 Hardware Design Guide
1VV0301352 Rev. 18
Page 47 of 75
2022-01-04
Not Subject to NDA
6.6.4.
General Purpose I/O
The general-purpose I/O pins can be configured to act in three different ways:
•
Input
•
Output
•
Dedicate Function (Customer Requirement)
Input pins can only be read and report digital values (high or low) present on the pin at
the read time. Output pins can only be written or queried and set the value of the pin
output.
The following GPIOs are always available as a primary function on the LM940.
Below table lists the GPIO signals of LM940.
Pin
Signal
I/O
Function
Type
Drive Strength
3
GPIO_01
I/O
Configurable GPIO
Pull-Down 1.8V
2-16 mA
5
GPIO_02
I/O
Configurable GPIO
Pull-Down 1.8V
2-16 mA
44
GPIO_03
I/O
Configurable GPIO
Pull-Down 1.8V
2-16 mA
46
GPIO_04
I/O
Configurable GPIO
Pull-Up 1.8V
2-16 mA
45
GPIO_05
I/O
Configurable GPIO
Pull-Down 1.8V
2-16 mA
47
GPIO_06
I/O
Configurable GPIO
Pull-Down 1.8V
2-16 mA
49
GPIO_07
I/O
Configurable GPIO
Pull-Down 1.8V
2-16 mA
51
GPIO_08
I/O
Configurable GPIO
Pull-Down 1.8V
2-16 mA
Table 30: LM940 GPIOs
6.6.4.1.
Using a GPIO Pin as Input
GPIO pins, when used as inputs, can be tied to a digital output of another device, and
report its status, provided the device interface levels are compatible with the GPIO 1.8V
CMOS levels.
If a digital output of a device is tied to GPIO input, the pin has interface levels different
than 1.8V CMOS. It can be buffered with an open collector transistor with a 47 k
Ω
pull-up
resistor to 1.8V.