Datasheet

ADT7470 Data Sheet
Rev. E | Page 8 of 40
GENERAL-PURPOSE I/O PINS (OPEN DRAIN)
The ADT7470 has four pins that can be configured as either general-purpose logic pins or as PWM outputs. Each GPIO pin has a
corresponding enable, direction, polarity and status bit.
Pin Function Register Address and Bit
GPIO1 Enable 0x7F [3]
Direction 0x80 [7]
Polarity 0x80 [6]
Status 0x81 [4]
GPIO2 Enable 0x7F [2]
Direction 0x80 [5]
Polarity 0x80 [4]
Status 0x81 [5]
GPIO3 Enable 0x7F [1]
Direction 0x80 [3]
Polarity 0x80 [2]
Status 0x81 [6]
GPIO4 Enable 0x7F [0]
Direction 0x80 [1]
Polarity 0x80 [0]
Status 0x81 [7]
To enable the PWM output on the ADT7470 as GPIOs, the enable bits in Register 0x7F must be set to 1.
Setting a direction bit to 1 in the GPIO configuration register makes the corresponding GPIO pin an output. Clearing the direction bit to
0 makes it an input.
Setting a polarity bit to 1 makes the corresponding GPIO pin active high. Clearing the polarity bit to 0 makes it active low.
When a GPIO pin is configured as an input, the corresponding bit in the GPIO status register is read-only and is set when the input is
asserted. When a GPIO pin is configured as an output, the corresponding bit in one of the GPIO status registers becomes read/write.
Setting this bit asserts the GPIO output. Note that whether a GPIO pin is configured as an input or as an output, asserted can be high or
low, depending on the setting of the polarity bit.