FUNCTIONAL DEVICE OPERATION
OPERATING MODES
When SPI controlled (Watchdog, On, and User Off Wait states), the PWGTDRVx power gate drive pin states are determined
by SPI enable bits PWGTxSPIEN, according to Table 39.
Table 39. Power Gating Logic Table
PWGTxSPIEN
PWGTDRVx
1
0
Low
High
Notes
56. Applicable for Watchdog, On and User Off Wait modes
only. If PWGT1SPIEN AND PWGT2SPIEN both = 1 then
the charge pump is disabled.
GENERAL PURPOSE OUTPUTS
GPO drivers included can provide useful system level signaling with SPI enabling and programmable Standby control. Key
use cases for GPO outputs include battery pack thermistor biasing and enabling of peripheral devices, such as light sensor(s),
camera flash, or even supplemental regulators.
SPI enabling can be used for coordinating GPOs with ADC conversions for consumption efficiency and desired settling
characteristics.
Four general purpose outputs are provided, summarized in Table 40 and Table 41 (active high polarities assumed).
Table 40. GPO Control Bits
SPI Bit
GPOxEN
GPO Control
GPOx enable
GPOx controlled by STANDBY
GPOxSTBY
x = 1, 2, 3, or 4
Table 41. GPO Control Scheme
GPOxEN
GPOxSTBY
STANDBY
Output GPOx
0
1
1
1
X
0
1
1
X
X
0
Low
High
High
Low
1
Notes
57. GPO1 is automatically made active high when a charger is
detected, see Battery Interface and Control for more
information.
The GPO1 output is intended to be used for battery thermistor biasing. For accurate thermistor reading by the ADC, the output
resistance of the GPO1 driver is of importance; see ADC Subsystem.
Table 42. GPO1 Driver Output Characteristics
Parameter
Condition
Min
Typ
Max
Units
GPO1 Output Impedance
Output VCORE Impedance to VCORE
200
500
Ohm
Finally, a muxing option is included to allow GPO4 to be configured for a muxed connection into Channel 7 of the GP ADC.
As an application example, for a dual light sensor application, Channel 7 can be toggled between the ADIN7 (ADINSEL7 = 00)
and GPO4 (ADINSEL7 = 11) for convenient connectivity and monitoring of two sensors. The GPO4 pin is configured for ADC
input mode by default (GPO4ADIN = 1) so that the GPO driver stage is high-impedance at power up. The GPO4 pin can be
configured by software for GPO operation with GPO4ADIN = 0. Refer to ADC Subsystem for GP ADC details.
13892
Analog Integrated Circuit Device Data
70
Freescale Semiconductor
FREESCALE [ Freescale ]
