Datasheet
790
SAM4S Series [DATASHEET]
11100F–ATARM–29-Jan-14
• MODE9: 9-bit Character Length
0: CHRL defines character length.
1: 9-bit character length.
• CLKO: Clock Output Select
0: The USART does not drive the SCK pin.
1: The USART drives the SCK pin if USCLKS does not select the external clock SCK.
• OVER: Oversampling Mode
0: 16x Oversampling.
1: 8x Oversampling.
• INACK: Inhibit Non Acknowledge
0: The NACK is generated.
1: The NACK is not generated.
• DSNACK: Disable Successive NACK
0: NACK is sent on the ISO line as soon as a parity error occurs in the received character (unless INACK is set).
1: Successive parity errors are counted up to the value specified in the MAX_ITERATION field. These parity errors generate a
NACK on the ISO line. As soon as this value is reached, no additional NACK is sent on the ISO line. The flag ITERATION is
asserted.
• INVDATA: Inverted Data
0: The data field transmitted on TXD line is the same as the one written in US_THR register or the content read in US_RHR is the
same as RXD line. Normal mode of operation.
1: The data field transmitted on TXD line is inverted (voltage polarity only) compared to the value written on US_THR register or
the content read in US_RHR is inverted compared to what is received on RXD line (or ISO7816 IO line). Inverted mode of opera-
tion, useful for contactless card application. To be used with configuration bit MSBF.
• VAR_SYNC: Variable Synchronization of Command/Data Sync Start Frame Delimiter
0: User defined configuration of command or data sync field depending on MODSYNC value.
1: The sync field is updated when a character is written into US_THR register.
• MAX_ITERATION: Maximum Number of Automatic Iteration
0–7: Defines the maximum number of iterations in mode ISO7816, protocol T = 0.
• FILTER: Infrared Receive Line Filter
0: The USART does not filter the receive line.
1: The USART filters the receive line using a three-sample filter (1/16-bit clock) (2 over 3 majority).
• MAN: Manchester Encoder/Decoder Enable
0: Manchester encoder/decoder are disabled.
1: Manchester encoder/decoder are enabled.
• MODSYNC: Manchester Synchronization Mode
0:The Manchester start bit is a 0 to 1 transition
1: The Manchester start bit is a 1 to 0 transition.