K60P100M100SF2RM Datasheet, PDF (1515/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

Field
7–5
Reserved
4
ONACK
3
ANACK
2
INIT
1
TTYPE
0
ISO_7816E
Chapter 51 Universal Asynchronous Receiver/Transmitter (UART)
UARTx_C7816 field descriptions
Description
This read-only field is reserved and always has the value zero.
Generate NACK on Overflow
When this bit is set, the receiver will automatically generate a NACK response if a receive buffer overrun
occurs as indicated by the S1[OR] field. In many systems this will result in the transmitter resending the
packet that overflowed until the retransmit threshold for that transmitter has been reached. A NACK is
only generated if TTYPE=0. This bit operates independently of ANACK. See Overrun NACK
considerations.
0 The received data does not generate a NACK when the receipt of the data results in an overflow
event.
1 If the receiver buffer overflows, a NACK is automatically sent on a received character.
Generate NACK on Error
When this bit is set, the receiver will automatically generate a NACK response if a parity error occurs or if
INIT is set and an invalid initial character is detected. A NACK is only generated if TTYPE = 0. If ANACK
is set the UART will attempt to retransmit the data indefinitely. To stop retransmission attempts, clear
C2[TE] or ISO_7816E and do not set until S1[TC] set C2[TE] again.
0 No NACK is automatically generated.
1 A NACK is automatically generated if a parity error is detected or if an invalid initial character is
detected.
Detect Initial Character
When this bit is set, all received characters will be searched for a valid initial character. If an invalid initial
character is identified then a NACK will be sent if ANACK is set. All received data is discarded and error
flags blocked (S1[NF], S1[OR], S1[FE], S1[PF], IS7816[WT], IS7816[CWT], IS7816[BWT], IS7816[GTV])
until a valid initial character is detected. Upon detection of a valid initial character the configuration values
S2[MSBF], C3[TXINV] and S2[RXINV] are automatically updated to reflect the initial character that was
received. The actual INIT data value is not stored in the receive buffer. Additionally, upon detection of a
valid initial character the IS7816[INITD] flag is set and an interrupt issued as programmed by the
IE7816[INITDE] bit. When a valid initial character is detected the INIT bit is automatically cleared.
0 Normal operating mode. Receiver does not seek to identify initial character.
1 Receiver searches for initial character.
Transfer Type
This bit indicates the transfer protocol being used.
Refer to ISO-7816 / smartcard support for more details.
0 T = 0 Per the ISO-7816 specification.
1 T = 1 Per the ISO-7816 specification.
ISO-7816 Functionality Enabled
This bit indicates that the UART is operating according to the ISO-7816 protocol.
NOTE: This bit should only be modified when no transmit or receive is occurring. If this bit is changed
during a data transfer the data being transmitted or received may be transferred incorrectly.
0 ISO-7816 functionality is turned off / not enabled.
1 ISO-7816 functionality is turned on / enabled.
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc.
1515