LP3958 Datasheet, PDF (18/28 Pages) National Semiconductor (TI) – Lighting Management Unit with High Voltage Boost Converter

General Purpose I/O Functionality
LP3958 has three general purpose I/O pins: GPIO[0]/PWM,
GPIO[1] and GPIO[2]. GPIO[0]/PWM can also be used as a
PWM input for the external LED PWM controlling. GPIO
bi-directional drivers are operating from the V_DDIO supply
domain.
Registers for GPIO are as follows:
GPIO CONTROL (06H)
Name
Bit
Description
EN_PWM_PIN
4
Enable PWM pin
0 = disable
1 = enable
OEN[2:0]
2:0 GPIO pin direction
0 = input
1 = output
Name
DATA[2:0]
GPIO DATA (07H)
Bit
Description
2:0
Data bits
GPIO control register is used to set the direction of each
GPIO pin. For example, by setting OEN0 bit high the
GPIO[0]/PWM pin acts as a logic output pin with data de-
fined DATA0 in GPIO data register. Note, that the EN_PW-
M_PIN bit overrides OEN0 state by forcing GPIO[0]/PWM to
act as PWM input. GPIO[1] and GPIO[2] pins can be se-
lected to be inputs or outputs, defined by OEN1 and OEN2
bit status. PWM functionality is valid only for GPIO[0]/PWM
pin. GPIO data register contains the data of GPIO pins.
When output direction is selected to GPIO pin, then GPIO
data register defines the output pin state. When GPIO data
register is read, it contains the state of the pin despite of the
pin direction.
Logic Interface Characteristics
(V_DDIO = 1.65V...V_DD1,2 unless otherwise noted)
Symbol
Parameter
Conditions
LOGIC INPUT SCL, SDA, GPIO[0:2]
V_IL
Input Low Level
V_IH
Input High Level
I_I
Logic Input Current
f_SCL
Clock Frequency
LOGIC INPUT NRST
V_IL
Input Low Level
V_IH
Input High Level
I_I
Input Current
t_NRST
Reset Pulse Width
LOGIC OUTPUT SDA
V_OL
Output Low Level
V_OH
Output High Level
I_L
Output Leakage Current
LOGIC OUTPUT GPIO[0:2]
I_SDA = 3mA
I_SDA = -3mA
V_SDA = 2.8V
V_OL
V_OH
I_L
Output Low Level
Output High Level
Output Leakage Current
I_GPIO = 3 mA
I_GPIO = −3 mA
V_GPIO = 2.8V
Min
0.8xV_DDIO
−1.0
1.2
-1.0
10
V_DDIO − 0.5
V_DDIO − 0.5
Typ
0.3
V_DDIO − 0.3
0.3
V_DDIO − 0.3
Max
0.2xV_DDIO
1.0
400
0.5
1.0
0.5
1.0
0.5
1.0
Units
V
V
µA
kHz
V
V
µA
µs
V
µA
V
V
µA
www.national.com
18