Gemalto Cinterion BGS5T USB, Hardware Interface Overview

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Cinterion
®
Java Terminals Hardware Interface Overview
3.6 GPIO Interface
39
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EHSxT_BGS5T_HIO_v03 2016-05-26
Confidential / Released
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3.6.4 SPI Interface
For EHS6T Java Terminals four GPIO interface pins can be configured as Serial Peripheral In-
terface (SPI). The SPI is a synchronous serial interface for control and data transfer between
Java Terminals and the external application. Only one application can be connected to the SPI
and the interface supports only master mode. The transmission rates are up to 6.5Mbit/s. The
SPI interface comprises the two data lines MOSI and MISO, the clock line SPI_CLK a well as
the chip select line SPI_CS.
The following pins at the GPIO connector can be configured as SPI interface signals: SPI_CLK,
SPI_MOSI, SPI_MISO and SPI_CS (see also
Table 13 ). The configuration is done by AT com-
mand (see [1] ). It is non-volatile and becomes active after a module restart.
To configure and activate the SPI interface use the AT^SSPI command. Detailed information
on the AT^SSPI command as well explanations on the SPI modes required for data transmis-
sion can be found in
[1] . SPI, ADC1_IN and DSR0 functionalities are mutually exclusive.
In general, SPI supports four operation modes. The modes are different in clock phase and
clock polarity. The module’s SPI mode can be configured by using the AT command AT^SSPI.
Make sure the module and the connected slave device works with the same SPI mode.
Figure 9 shows the characteristics of the four SPI modes. The SPI modes 0 and 3 are the most
common used modes.
Figure 9: Characteristics of SPI modes
SPI MODE 0 SPI MODE 1
SPI MODE 2 SPI MODE 3
Clock phase
Clock polari
ty
SPI_CS
MOSI
SPI_CLK
MISO
SPI_CS
MOSI
SPI_CLK
MISO
SPI_CS
MOSI
SPI_CLK
MISO
SPI_CS
MOSI
SPI_CLK
MISO
Sample Sample
Sample Sample