Rainbow Electronics ATR0635P1 - Manual (Page 19)

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4979D–GPS–06/08
ATR0635P1
3.5 Connecting an Optional Serial EEPROM
The ATR0635P1 offers the possibility of connecting an external serial EEPROM. The internal
ROM firmware supports storing the configuration of the ATR0635P1 in serial EEPROM. The pin
P16/NEEPROM signals the firmware that a serial EEPROM is connected to the ATR0635P1.
The ATR0635P1’s 32-bit RISC processor accesses the external memory via SPI (serial periph-
eral interface). For best results, use a 32-Kbit 1.8V serial EEPROM such as Atmel’s
AT25320AY1-1.8.
Figure 3-3 shows an example of the serial EEPROM connection.
Figure 3-3. Example of a Serial EEPROM Connection
Note: The GPSMODE pin configuration feature can be disabled, because the configuration can be
stored in the serial EEPROM. VDDIO is the supply voltage for the pins: P23, P24, P25 and P29.
AT25320AY1-1.8
ATR0635P1
SCK
SI
SO
CS_N
NC
GND
GND
HOLD_N
WP_N
P23/SCK
P25/MISO/NAADET0
P24/MOSI
P29/NPCS3
P16/NEEPROM
P1/GPSMODE0
(see Power Supply)
+3V
NC: Not connected
LDO_IN
LDOBAT_IN
VDDIO
VDD18
LDO_OUT
LDO_EN
NSHDN
GND