User Manual

Table Of Contents
Application layers
99-137719-D Confidential - For internal use 8-31
8888
Control interface
The flow of messages between the USIM HW driver and the USIM module are ISO 7816
APDUs. The APDU is an application level protocol as specified in the ISO 7816-4, which
takes place between the USIM card (connected to the BP) and a host application
(implemented in the RM).
There are two categories of APDUs:
C-APDU, Command APDU sent from the USIM module to the USIM card
R-APDU, Response APDU sent from the USIM card to the USIM module in the RM as
a response to a C-APDU.
The Board Processor must inform the RM when the USIM card is inserted and ready to
receive C-APDUs, or when the USIM card is disconnected. This is done using the
platform.usim.status parameter as illustrated below.
8.5.3.1 MSG_USIM_CAPDU
Command Application Protocol Data Unit (ISO/IEC 7816-4 5.3). This packed structure
covers the four cases of ISO/IEC 7816-4 C-APDU format. The C-APDU contains a
mandatory header of 4 bytes (CLA, INS, P1, P2) and a body with variable length. The
data length of the C-APDU body is coded into the body itself and depends on which of
the four cases the C-APDU represents.
Figure 8-17: Typical USIM setup
Figure 8-18: Typical USIM flow
USIM module
Radio
Module
Control
interface
Board
Processor
Control
interface
USIM hw
driver
USIM
card
R-APDUs
C-APDUs
Contr ol Interface serial link
RM BP
platform.usim.status = 1
USIM card inserted
and ready
RM allowed to
send C-APDUs
MSG_USIM_CAPDU
MSG_USIM_RAPDU