5.8 Powering the Module ON and OFF (ON/OFF)

Pin

 

Name

 

Direction

 

Function

 

 

 

 

 

 

 

14

 

ON/OFF

 

Input

 

Device on/off control

 

 

 

 

 

 

 

5.8.1 Turning the Module On

Figure 5.8-1 Power On timing

The GR64 power ON sequence is shown above. The significant signals are VCC, ON/OFF and VREF, shown by solid lines. The other signals (in dashed lines) are internal to the module and are shown for reference purposes only.

Initially, power is supplied to the VCC pins. The presence of power raises the ON/OFF through a pull-up resistor to VCC potential. In order to power the module, ON/OFF is pulled to ground. Once ON/OFF has been held low for 125ms (denoted by t1) the primary LDOs power up; the VREF signal comes from one of the primary LDOs. For module variants where VREF supplies a reference voltage to the host, it acts as a useful indicator that the baseband is powered.

When the VREF is configured as an input, it cannot be used as a power indicator.

NOTE

LZT 123 1834

47