NXP Semiconductors K32 L2A Series, Reference Manual, Page: 522 / 1379

each character that is transmitted with the current value of the LRC. If the
XMT_CRC_LRC bit in the CTRL register is set, the LRC value will automatically be
sent by the transmitter as the final character when the transmit FIFO empties.
The LRC value can be reset in multiple ways. Clearing the LCR_EN bit in the CTRL
register will reset the LRC value. At the end of a transmission (either after the LRC byte
is transmitted, or after the last character in the transmit FIFO is sent when
XMT_CRC_LRC is clear), the LRC value is automatically reset by the EMV SIM
hardware. Finally, when setting the XMT_EN bit, the EMV SIM hardware resets the
LRC value.
Summary of configuration needed to use LRC block:
• Use the LRC_EN bit in CTRL register to enable the LRC block
• Use the XMT_CRC_LRC bit to enable the transmission of the LRC Character after
the last character in the Transmit FIFO is sent.
21.6.5.2 CRC Block
The EMV SIM module provides an 16-bit Cyclic Redundancy Check (CRC) generator /
checker. The block is provided for use with T=1 Smart Cards that support CRC. This
block can be enabled through the CRC_EN bit in the CTRL register. This block performs
a polynomial based check on all received or transmitted characters. The polynomial used
for calculating the CRC is G(x) = x
16
+ x
12
+ x
5
+ 1. The CRC register is initialized to all
“1” before the data is shifted in. The CRC block can be configured to compute using the
ISO 7816 CRC method or the 16-bit CCITT CRC method. The software can select the
following bits: CRC_IN_FLIP, CRC_OUT_FLIP, and INV_CRC_VAL of the CTRL
register.
• To select CCITT CRC method, set
• CRC_IN_FLIP = 1
• CRC_OUT_FLIP = 1
• INV_CRC_VAL = 1
• To select normal CRC method (i.e. ISO 7816 CRC method), set
• CRC_IN_VAL = 0
• CRC_OUT_VAL = 0
• INV_CRC_VAL = 1
During transmission, the CRC block updates the current value of the CRC using each
character. If the XMT_CRC_LRC bit in the CTRL register is set, the CRC value will
automatically be formatted as per the selected CRC method (CCITT or normal) and sent
by the EMV SIM transmitter as the final two characters when the transmit FIFO empties.
At the end of the reception of a block of characters, the residual from the CRC
calculation is compared and the CRC_OK bit is set in the RX_STATUS register.
Functional Description
K32 L2A Reference Manual, Rev. 2, 01/2020
522 NXP Semiconductors