ATR0621 Datasheet, PDF (16/20 Pages) ATMEL Corporation – GPS Baseband Processor

Table 3-15. Recommended Pin Connection (Continued)
Pin Name
Recommended External Circuit
P19/SIGLO2/GPSMODE6
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application; connect to
GND or VDD18 if unused or used as GPSMODE pin only. See GPSMODE definitions in “Setting
GPSMODE0 to GPSMODE12” on page 10. Can be left open if not used as GPSMODE pin and
configured as output by user application.
P20/SCK2/TIMEPULSE
Output in default ROM firmware: leave open; only needs pull-up resistor to VDD18 or pull-down resistor
to GND if used as GPIO input by user application and not always driven from external sources.
P21/TXD2
Output in default ROM firmware: leave open; only needs pull-up resistor to VDD18 or pull-down resistor
to GND if used as GPIO input by user application and not always driven from external sources.
P22/RXD2
Pull-up resistor to VDD18 or connect to VDD18 if unused. Pull-down resistor also possible if used as
GPIO input by user application. Never leave open.
P23/SCK/GPSMODE7
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application; connect to
GND or VDD18 if unused or used as GPSMODE pin only. See GPSMODE definitions in “Setting
GPSMODE0 to GPSMODE12” on page 10. Can be left open if not used as GPSMODE pin and
configured as output by user application.
P24/MOSI/GPSMODE8
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application; connect to
GND or VDD18 if unused or used as GPSMODE pin only. See GPSMODE definitions in “Setting
GPSMODE0 to GPSMODE12” on page 10. Can be left open if not used as GPSMODE pin and
configured as output by user application.
P25/MISO/GPSMODE9
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application; connect to
GND or VDD18 if unused or used as GPSMODE pin only. See GPSMODE definitions in “Setting
GPSMODE0 to GPSMODE12” on page 10. Can be left open if not used as GPSMODE pin and
configured as output by user application.
P26/NSS/NPCS0/
GPSMODE10
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application; connect to
GND or VDD18 if unused or used as GPSMODE pin only. See GPSMODE definitions in “Setting
GPSMODE0 to GPSMODE12” on page 10. Use pull-up resistor to VDD18, if SPI is used. Never leave
open.
P27/NPCS1/GPSMODE11
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application; connect to
GND or VDD18 if unused or used as GPSMODE pin only. See GPSMODE definitions in “Setting
GPSMODE0 to GPSMODE12” on page 10. Can be left open if not used as GPSMODE pin and
configured as output by user application.
P28/EM_A20/NPCS2
Output in default ROM firmware: leave open; only needs pull-up resistor to VDD18 or pull-down resistor
to GND if used as GPIO input by user application and not always driven from external sources.
P29/NPCS3/GPSMODE12
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application; connect to
GND or VDD18 if unused or used as GPSMODE pin only. See GPSMODE definitions in “Setting
GPSMODE0 to GPSMODE12” on page 10. Can be left open if not used as GPSMODE pin and
configured as output by user application.
P30/AGCOUT0
Internal pull-up resistor, leave open.
P31/RXD1
Pull-up resistor to VDD18 or connect to VDD18 if unused. Pull-down resistor also possible if used as
GPIO input by user application. Never leave open.
EM_DA0 to EM_DA15
If no external memory is used, can be left open (internal pull-down). If an external memory is connected
to these pins, a defined level is needed when all external memories are inactive.
Note: “Never leave open” means: This pin needs a defined level, even if VDD18 is not supplied and system is in backup mode.
16 ATR0621 [Preliminary]
4890AS–GPS–09/05