Interfaces; Host Port Uart; Host Port Spi - Fibocom GTS-4E-00 Hardware Integration Manual

ID151 & 167.

Adaptive TricklePower (ATP): In this mode the receiver stays at full on power state for 200...
900ms and provides a valid fix. Between fixes with 1... 10 sec interval the receiver stays in
Hibernate state. ATP mode is configurable with SiRF binary protocol message ID151. The receiver
stays once in while in Full on power mode automatically (typ.every 1800 sec) to receive new
ephemeris data from rising satellites or if received signal levels drop below certain level.
2.2

Interfaces

There are two communication interfaces, Uart and SPI, for user port. It is valid for different part
number(refer to Table 1：Naming rule of Part Number).
For uart port the default protocol for host communication is NMEA 4800 baud. Protocol is switchable to
SiRF binary OSP (One Socket Protocol) by NMEA protocol command $PSRF100.
Default NMEA message configuration: $GPGGA, $GPGSA and $GPRMC rate every second (in this
order) and $GPGSV messages (can be 1... 4) every 5 seconds (sent after $GPGSA message).
GTS-4E also offer a I2C bus for external EEPROM and Accelerometer, it is valid in some part number.
2.2.1

Host Port UART

UART is normally used for GPS data reports and receiver control. Serial data rates are selectable from
1200 baud to 1.8432 Mbaud. Default baud rate is 4800 baud; default protocol is NMEA(protocol and
baud rate can be configured by NMEA $PSRF100 message). RX signal is suggested to be pulled up
externally when not used.
2.2.2

Host Port SPI

The host interface SPI is a slave mode SPI:

Supports both SPI and Microwire formats

An interrupt is provided when the transmit FIFO and output serial register (SR) are both empty

The transmitter and receiver each have independent 1024B FIFO buffers

The transmitter and receiver have individual software-defined 2-byte idle patterns of 0xA7 0xB4

Clock polarity: default SPI mode 1 (CPOL=0; CPHA=1) i.e. data is captured on the clock's
falling edge and data is propagated on a rising edge

SPI detects synchronization errors and is reset by software
GTS-4E GPS Module Hardware Integration Manual Page 8 of 22