K60P100M100SF2RM Datasheet, PDF (1550/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Functional description
Additionally the module is able to provide automated NACK responses and has
programing automated retransmission of failed packets. An assortment of programmable
timeouts and guard band times are also supported.
The term elemental time unit (ETU) is frequently used in the context of ISO-7816. This
concept is used to relate the frequency that the system (UART) is running at and the
frequency that data is being transmitted and received. One ETU represents the time it
takes to transmit or receive a single bit. For example, a standard 7816 packet, excluding
any guard time or NACK elements is 10 ETUs (start bit, 8 data bits and a parity bit).
Guard times and wait times are also measured in ETUs.
NOTE
The ISO-7816 specification may have certain configuration
options that are reserved. In order to maintain maximum
flexibility to support future 7816 enhancements or devices
which may not strictly conform to the specification, the UART
does not prevent those options being used. Further, the UART
may provide configuration options that exceed the flexibility of
options explicitly allowed by the 7816 specification. Failure to
correctly configure the UART may result in unexpected
behavior or incompatibility with the ISO-7816 specification.
51.4.7.1 Initial characters
In ISO-7816 mode, the UART can be configured to use the C7816[INIT] bit to detect the
next valid initial character, referred to by the ISO-7816 specifically as a TS character.
When the initial character is detected, the UART provides the host processor with an
interrupt if IE7816[INITDE] is set. Additionally, the UART will set the S2[MSBF],
C3[TXINV] and S2[RXINV] register fields automatically based on the initial character.
The corresponding initial character and resulting register settings are listed in the
following table.
Table 51-204. Initial character automated settings
Initial character (bit 1-10)
LHHL LLL LLH
inverse convention
LHHL HHH LLH
direct convention
Initial character
(hex)
3F
3B
MSBF
1
0
TXINV
1
0
RXINV
1
0
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K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.