User manual

Hardware Description

The StampA5D3x integrates two CAN controllers, CAN0 and CAN1. The CAN controller is

not present on all variations of the StampA5D3x series. Compare Table2.1, “SAMA5D3X

Device Differences”.

5.26. Software Modem Device (SMD)

The SMD is a block for communication via a modem's Digital Isolation Barrier (DIB) with

a complementary Line Side Device (LSD). Power and clock are supplied by the SMD and

consumed by the LSD. The data flow is bidirectional. The data transfer is based on pulse

width modulation for transmission from the SMD to the LSD, and for receiving from the

LSD.

It has two bidirectional channels, a data and a control channel. The data channel is used

to transfer digitized signal samples at a constant rate of 16 bits at 16 kHz, whereas the

control channel is used to communicate with control regiters of the LSD at a maximum

rate of 8 bits at 16 kHz.

5.27. Universal Sychronous Asynchronous Receiver and

Transmitter (USART)

The StampA5D3x has up to four independent USARTs and two UARTs, not including

the debug unit. The UARTS are not present on all variations of the StampA5D3x series.

Compare Table2.1, “SAMA5D3X Device Differences”.

The Universal Synchronous Asynchronous Receiver Transceiver (USART) provides one

full duplex universal synchronous asynchronous serial link. Data frame format is widely

programmable (data length, parity, number of stop bits) to support a maximum of

standards. The receiver implements parity error, framing error and overrun error

detection. The receiver time-out 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 supports the connection to the Peripheral DMA Controller, which enables

data transfers to the transmitter and from the receiver. The PDC provides chained buffer

management without any intervention of the processor.

Six different modes are implemented within the USARTs:

• Normal (standard RS232 mode)

• RS485

• Hardware Handshaking

• ISO7816 Protocol: T=0 or T=1

• IrDA

RS485. In RS485 operating mode the RTS pin is automatically driven high during

transmit operations. If RTS is connected to the "enable" line of the RS485 driver, the driver

will thus be enabled only during transmit operations.