Rainbow Electronics ATR0621 - Manual (Page 16)

16
4890AS–GPS–09/05
ATR0621 [Preliminary]
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.
Table 3-15. Recommended Pin Connection (Continued)
Pin Name Recommended External Circuit
Note: “Never leave open” means: This pin needs a defined level, even if VDD18 is not supplied and system is in backup mode.