4117047
Rev 2.2
December 18, 2015
22
Product Technical Specification
Detailed Interface Specifications
2.5. VGPIO
The VGPIO output can be used to:
Pull-up signals such as I/Os
Supply the digital transistors driving LEDs
Act as a voltage reference for the ADC interfaces, ADC0 and ADC1
The VGPIO output is available when the AirPrime HL8518, HL8528 and HL8529 module is switched
ON.
2.5.1.
Electrical Characteristics
The following table describes the electrical characteristics of the VGPIO interface.
Table 10. VGPIO Electrical Characteristics
Parameter
Min
Typ
Max
Remarks
Voltage level (V)
1.7
1.8
1.9
Both active mode and sleep mode
Current capability active
mode (mA)
-
-
50
Power Management support up to 50mA output.
Rise Time(ms)
-
-
1.5
Start-Up time from 0V
2.5.2.
Pin Description
The following table describes the pin description of the VGPIO interface.
Table 11. VGPIO Pin Description
Pin Number
Signal Name
I/O
I/O Type
Function
45
VGPIO
O
1.8V
(Power supply) GPIO voltage output
2.6. BAT_RTC
The AirPrime HL8518, HL8528 and HL8529 modules provide an input/output to connect a Real Time
Clock power supply.
This pin is used as a back-up power supply for the internal Real Time Clock. The RTC is supported
when VBATT is available but a back-up power supply is needed to save date and hour when VBATT
is switched off.
If VBATT is available, the back-up battery can be charged by the internal 1.8V power supply regulator.
