35.6.3 USART Signal Descriptions

Table 35-5. SERCOM USART Signal Descriptions
Signal NamesFunctionPin TypeDescription

SERCOMn_PAD[0]

SERCOMn_PAD[1]

SERCOMn_PAD[2]

SERCOMn_PAD[3]

TXDDigital OutputUSART TX Transmit Data
RXDDigital InputUSART RX Receive Data
XCKDigital Input/OutputUSART external clock input or output
RTSDigital OutputUSART Flow Control “Request-To-Send” output
CTSDigital InputUSART Flow Control “Clear-To-Send” Input
TEDigital OutputUSART “Transmit Enable” output in RS485 mode
Table 35-6. USART User Configuration Summary
CMODEFORMTXPORXPOSAMPRENCLINCMDPMODEMODEHOSTCLIENTTXINVRXINVDORDCHSIZETXEN/RXEN

/ENABLE

SBMODEGTIMERTS/CTS/TECOMMENTS
1 (Sync)0x00x00x2—00—0NOYESXXX

0x0,

0x1,

0x5,

0x6,

0x7

1/1/10X—(Client) FD Sync, Ext Clk in
—1YESNOXX—(Host) FD Sync Ext Clk out
0x3—0NOYESXX—(Client) FD Sync Ext Clk in
—1YESNOXX—(Host) FD Sync Ext Clk out
0x10x2X0NOYESXX—(Client) FD Sync Ext Clk in
1YESNOXX—(Host) FD Sync Ext Clk out
0x30NOYESXX—(Client) FD Sync Ext Clk in
1YESNOXX—(Host) FD Sync Ext Clk out
0x70x000NOYES110x002—ISO 7816 (Client) HD Sync Ext Clk in
1YESNO—ISO 7816 (Host) HD Sync Ext Clk Out
0 (Async)0x00x00x2,30x0,0x2,0x4—1——XX

0x0,

0x1,

0x5,

0x6,

0x7

XX—RS-232 FD without Flow Control
0x20x1—1——XXRTS/CTSRS-232 FD w/Flow Control
0x30x3—1——XX1TERS-485 (HD/FD, No Flow Ctrl)
0x10x00x2,3X1——XXX—RS-232 FD without Flow Control
0x20x1X1——XXRTS/CTSRS-232 FD w/Flow Control
0x30x3X1——XX1TERS-485 (HD/FD, No Flow Ctrl)
0x20x00x2,30x0,0x10x2—1YESNO0010X——LIN Host – HDW Break, Sync, and ID generation
0x1LIN Host – HDW Break gen, SW Sync and SW ID generation
0x40x00x2,30x1——1NOYES0010X——Auto-baud (LIN Client) - break detection (Fractional Baud)
0x50x00x2,3—X1NOYES0010X——Auto-baud (LIN Client) - break detection w/parity (Fractional Baud)
0x00x00x2,301——1——00X0X——IRDA FD Transceiver
Legend

X = Application specific, user selectable

HD = Half Duplex

FD = Full Duplex

— = Not applicable