PHD User Guide
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7. HMI (Human Machine Interface)
The PHD family has an easy to use graphical user interface consisting of a color LCD and touchscreen
with the option of adding a keypad.
7.1. Ambient light sensor
The PHD70 display, if enabled, will automatically adjust the display’s backlight, based on the amount of
ambient light. The ambient light is sensed and measured via the sensor opening on the glass face. At
1000 lux or greater the backlight is at full brightness when the auto adjustment is enabled.
7.2. Touchscreen
The display uses a capacitive touchscreen and the host CPU controls the power and reset with the
touchscreen providing an interrupt back to the host. If the touchscreen interface is required as a wakeup
source, then the host must leave power on the interface and the TP must not be in reset when the host
goes to sleep. There is a series of commands that must be written to the touchscreen controller to ensure
that it’s in its lowest power mode. The interrupt for wakeup will be driven to the host CPU as well as the
power CPU.
7.3. Keypad
The PHD family of displays does not have an integral keypad. The PHD will support an external keypad
(e.g. four button interface, five button interface, 10+ key grid keypad) via the GPIO and any or all of the
lines can act as a wakeup source.
7.4. Buzzer
The PHD units themselves do not house a buzzer. A regulated 12Vdc supply is provided from the pins of
the main connectors and this can be used to power a buzzer. Note that this interface is limited to 500mA.
To drive the other leg of an external buzzer, low-side output 1 or 2 can drive either a steady state low or a
PWM output to drive a buzzer. This low-side output is also capable of sinking 500mA.
7.5. Video
The PHD50 and PHD70 support analog video cameras.
•
PHD50 has 1 video input
•
PHD70 has 2 video inputs
The PHD50 supports one D1 resolution PAL/NTSC input.
The PHD70 supports dual D1 resolution PAL/NTSC inputs and can display both video feeds
simultaneously.