Rainbow Electronics ATR0621 - Manual (Page 15)

15
4890AS–GPS–09/05
ATR0621 [Preliminary]
Table 3-15. Recommended Pin Connection
Pin Name Recommended External Circuit
P0/NANTSHORT Internal pull-down resistor; can be left open.
P1/GPSMODE0
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 configured as output by user application. If
this pin is left open, the GPSMODE pin configuration feature must be completely disabled by user
application.
P2/BOOT_MODE Internal pull-down resistor, leave open.
P3/NCS1
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.
P4/NCS0
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.
P5/NWE/NWR0
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.
P6/NOE/NRD
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.
P7/NUB/NWR1
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.
P8/STATUSLED
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.
P9/EXTINT0
Pull-up resistor to VDD18 or pull-down resistor to GND or connect to GND or VDD18 if unused. Never
leave open.
P10/EM_A0/NLB
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.
P11/EM_A21
Pull-up resistor to VDD18 or pull-down resistor to GND (this pin is used as address line EM_A21 by
standard firmware, do not connect to GND or VDD18 directly). Never leave open.
P12/NCS2/GPSMODE2
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application, or 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.
P13/EXTINT1/GPSMODE3/
NCS3
Pull-up resistor to VDD18 or pull-down resistor to GND if used as input by user application, or connect to
GND or VDD18 if unused or used as GPSMODE pin only. See GPSMODE definitions in section
“Setting
GPSMODE0 to GPSMODE12” on page 10 . Never leave open.
P14/SCK0/GPSMODE4
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.
P15/ANTON Internal pull-down resistor; can be left open.
P16/NWD_OVF
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.
P17/SCK1/GPSMODE5
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.
P18/TXD1
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.
Note: “Never leave open” means: This pin needs a defined level, even if VDD18 is not supplied and system is in backup mode.