10.1.2 Interfacing in USART Mode

The SAMA7G54 SOM Series offers 11 FLEXCOM interfaces configured in USART mode.

The USART provides one full-duplex universal synchronous asynchronous serial link. The data frame format is widely programmable (data length, parity, number of stop bits) to support a high number of standards. The receiver implements parity error, framing error and overrun error detection. The receiver timeout enables handling variable-length frames and the transmitter timeguard facilitates communications with slow remote devices. Multidrop communications are also supported through address bit handling in reception and transmission.

The USART features three test modes: Remote Loopback, Local Loopback and Automatic Echo.

The USART supports specific operating modes providing interfaces on RS485, LIN, with ISO7816 T = 0 or T = 1 smart card slots, and infrared transceivers. The hardware handshaking feature enables an out-of-band flow control by automatic management of the pins RTS and CTS.

The USART supports the connection to the DMA Controller, which enables data transfers to the transmitter and from the receiver. The DMAC provides chained buffer management without any intervention of the processor.

Table 10-13. FLEXCOM0 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM0	1	125	PA0	Transmit Data (TXD)
		130	PA1	Receive Data (RXD)
		128	PA3	Clear To Send (CTS)
		121	PA4	Request To Send (RTS)

Table 10-14. FLEXCOM1 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM1	1	127	PA5	Transmit Data (TXD)
		124	PA6	Receive Data (RXD)
		131	PA12	Clear To Send (CTS)
		133	PA14	Request To Send (RTS)
FLEXCOM1	2	20	PD12	Transmit Data (TXD)
		21	PD13	Receive Data (RXD)
		19	PD15	Clear To Send (CTS)
		24	PD16	Request To Send (RTS)
FLEXCOM1	3	126	PA2	Transmit Data (TXD)
		128	PA3	Receive Data (RXD)
		19	PD15	Clear To Send (CTS)
		24	PD16	Request To Send (RTS)
FLEXCOM1	4	87	PC9	Transmit Data (TXD)
		88	PC10	Receive Data (RXD)
		19	PD15	Clear To Send (CTS)
		24	PD16	Request To Send (RTS)

Table 10-15. FLEXCOM2 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM2	1	123	PA7	Transmit Data (TXD)
		122	PA8	Receive Data (RXD)
		120	PA10	Clear To Send (CTS)
		129	PA11	Request To Send (RTS)
FLEXCOM2	2	23	PD17	Transmit Data (TXD)
		111	PD18	Receive Data (RXD)
		29	PD20	Clear To Send (CTS)
		26	PD21	Request To Send (RTS)
FLEXCOM2	3	121	PA4	Transmit Data (TXD)
		127	PA5	Receive Data (RXD)
		29	PD20	Clear To Send (CTS)
		26	PD21	Request To Send (RTS)
FLEXCOM2	4	89	PC11	Transmit Data (TXD)
		90	PC12	Receive Data (RXD)
		29	PD20	Clear To Send (CTS)
		26	PD21	Request To Send (RTS)

Table 10-16. FLEXCOM3 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM3	1	180	PA15	Transmit Data (TXD)
		179	PA16	Receive Data (RXD)
		177	PA18	Clear To Send (CTS)
		182	PA19	Request To Send (RTS)
FLEXCOM3	2	55	PC0	Transmit Data (TXD)
		56	PC1	Receive Data (RXD)
		58	PB30	Clear To Send (CTS)
		54	PB31	Request To Send (RTS)
FLEXCOM3	3	124	PA6	Transmit Data (TXD)
		123	PA7	Receive Data (RXD)
		58	PB30	Clear To Send (CTS)
		54	PB31	Request To Send (RTS)
FLEXCOM3	4	91	PC13	Transmit Data (TXD)
		92	PC14	Receive Data (RXD)
		58	PB30	Clear To Send (CTS)
		54	PB31	Request To Send (RTS)
FLEXCOM3	5	24	PD16	Transmit Data (TXD)
		23	PD17	Receive Data (RXD)
		58	PB30	Clear To Send (CTS)
		54	PB31	Request To Send (RTS)

Table 10-17. FLEXCOM4 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM4	1	175	PA20	Transmit Data (TXD)
		178	PA21	Receive Data (RXD)
		184	PA23	Clear To Send (CTS)
		183	PA24	Request To Send (RTS)
FLEXCOM4	2	57	PC2	Transmit Data (TXD)
		59	PC3	Receive Data (RXD)
		61	PC5	Clear To Send (CTS)
		62	PC6	Request To Send (RTS)
FLEXCOM4	3	122	PA8	Transmit Data (TXD)
		119	PA9	Receive Data (RXD)
		61	PC5	Clear To Send (CTS)
		62	PC6	Request To Send (RTS)
FLEXCOM4	4	93	PC15	Transmit Data (TXD)
		99	PC16	Receive Data (RXD)
		61	PC5	Clear To Send (CTS)
		62	PC6	Request To Send (RTS)
FLEXCOM4	5	111	PD18	Transmit Data (TXD)
		110	PD19	Receive Data (RXD)
		61	PC5	Clear To Send (CTS)
		62	PC6	Request To Send (RTS)

Table 10-18. FLEXCOM5 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM5	1	187	PA28	Transmit Data (TXD)
		188	PA29	Receive Data (RXD)
		186	PA27	Clear To Send (CTS)
		181	PA25	Request To Send (RTS)
FLEXCOM5	2	30	PD25	Transmit Data (TXD)
		36	PD26	Receive Data (RXD)
		35	PD28	Clear To Send (CTS)
		33	PD29	Request To Send (RTS)
FLEXCOM5	3	120	PA10	Transmit Data (TXD)
		129	PA11	Receive Data (RXD)
		35	PD28	Clear To Send (CTS)
		33	PD29	Request To Send (RTS)
FLEXCOM5	4	100	PC17	Transmit Data (TXD)
		101	PC18	Receive Data (RXD)
		35	PD28	Clear To Send (CTS)
		33	PD29	Request To Send (RTS)
FLEXCOM5	5	29	PD20	Transmit Data (TXD)
		26	PD21	Receive Data (RXD)
		35	PD28	Clear To Send (CTS)
		33	PD29	Request To Send (RTS)

Table 10-19. FLEXCOM6 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM6	1	6	PB2	Transmit Data (TXD)
		5	PB1	Receive Data (RXD)
		7	PB0	Clear To Send (CTS)
		3	PA30	Request To Send (RTS)

Table 10-20. FLEXCOM7 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM7	2	85	PC7	Transmit Data (TXD)
		86	PC8	Receive Data (RXD)
		88	PC10	Clear To Send (CTS)
		89	PC11	Request To Send (RTS)
FLEXCOM7	3	181	PA25	Transmit Data (TXD)
		185	PA26	Receive Data (RXD)
		88	PC10	Clear To Send (CTS)
		89	PC11	Request To Send (RTS)
FLEXCOM7	4	52	PB28	Transmit Data (TXD)
		53	PB29	Receive Data (RXD)
		88	PC10	Clear To Send (CTS)
		89	PC11	Request To Send (RTS)

Table 10-21. FLEXCOM8 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM8	1	144	PB8	Transmit Data (TXD)
		156	PB9	Receive Data (RXD)
		158	PB11	Clear To Send (CTS)
		157	PB12	Request To Send (RTS)
FLEXCOM8	2	92	PC14	Transmit Data (TXD)
		91	PC13	Receive Data (RXD)
		93	PC15	Clear To Send (CTS)
		99	PC16	Request To Send (RTS)
FLEXCOM8	3	186	PA27	Transmit Data (TXD)
		187	PA28	Receive Data (RXD)
		93	PC15	Clear To Send (CTS)
		99	PC16	Request To Send (RTS)
FLEXCOM8	4	58	PB30	Transmit Data (TXD)
		54	PB31	Receive Data (RXD)
		93	PC15	Clear To Send (CTS)
		99	PC16	Request To Send (RTS)

Table 10-22. FLEXCOM9 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM9	1	151	PB13	Transmit Data (TXD)
		155	PB14	Receive Data (RXD)
		152	PB16	Clear To Send (CTS)
		159	PB17	Request To Send (RTS)

Table 10-23. FLEXCOM11 Interface Configuration in USART Mode
Interface Instance	IO Set	Pin No.	Pin Name	Function
FLEXCOM11	1	139	PB3	Transmit Data (TXD)
		140	PB4	Receive Data (RXD)
		142	PB6	Clear To Send (CTS)
		143	PB7	Request To Send (RTS)
FLEXCOM11	3	5	PB1	Transmit Data (TXD)
		6	PB2	Receive Data (RXD)
		142	PB6	Clear To Send (CTS)
		143	PB7	Request To Send (RTS)
FLEXCOM11	4	60	PC4	Transmit Data (TXD)
		61	PC5	Receive Data (RXD)
		142	PB6	Clear To Send (CTS)
		143	PB7	Request To Send (RTS)