Chapter 2

Functional Overview

This chapter describes the major functional blocks of the ARM PrimeCell Smart Card Interface (PL131). It contains the following sections:

•ARM PrimeCell Smart Card Interface (PL131) overview on page 2-2

•PrimeCell SCI functional description on page 2-3

•PrimeCell SCI operation on page 2-8

•PrimeCell SCI DMA interface on page 2-25

•SCI clock stop mode on page 2-28

•PrimeCell SCI clock and data driver configurations on page 2-29.

Functional Overview

2.1ARM PrimeCell Smart Card Interface (PL131) overview

The PrimeCell Smart Card Interface (SCI) conforms to Part 1 of the Integrated Circuit Specification for Payment Systems Electromechanical Characteristics, Logical Interface, and Transmission Protocols (Version 3.1.1 May 31, 1998). This standard is published jointly by Europay International S.A., Mastercard International Incorporated, and Visa International Service Association and is subsequently referred to as the EMV Standard. This standard refers to, and is based on, the ISO 7816 series of standards. The user is expected to be familiar with both the EMV Standard and ISO 7816-3.

The PrimeCell SCI performs:

•serial to parallel conversion on data received

•parallel to serial conversion on data transmitted to an external smart card.

The host CPU reads and writes data and control information through the AMBA APB interface. The transmit and receive paths are buffered with internal FIFO memories allowing up to 8 bytes to be stored independently in both transmit and receive modes. Data can also be transferred through the DMA interface.

The PrimeCell SCI includes a programmable baud rate generator and, in conjunction with a secondary value counter, provides programmable elementary time units (etus).

The PrimeCell SCI has been designed to enable close monitoring of all stages of a typical card session using mask enabled interrupts. The interrupt architecture allows a choice of:

•a polled approach by examining the interrupt status register on assertion of a single common interrupt

•the interrupt sources can be fed directly to the interrupt controller for immediate identification.

The transmit and receive FIFO interrupts are asserted and deasserted automatically depending on their programmed trigger threshold levels.

Parity errors are automatically checked by hardware on received data.

Interpretation of the received data stream is always performed by the user’s application software.

Card deactivation is initiated automatically through hardware on card removal, but it is also possible to deactivate the card through software by writing to the respective control register. A second deactivation request input is available for direct control through an alternative hardware source.