Peripheral Architecture

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2.2Signal Descriptions

The UARTs utilize a minimal number of signal connections to interface with external devices. The UART signal descriptions are included in Table 3. Note that the number of UARTs and their supported features vary on each device, see the device-specific data manual for more details.

 

 

Table 3. UART Signal Descriptions

 

 

 

Signal Name (1)

Signal Type

Function

UTXDn

Output

Serial data transmit

URXDn

Input

Serial data receive

UCTSn

Input

Clear-to-Send handshaking signal

URTSn

Output

Request-to-Send handshaking signal

(1)The value n indicates the applicable UART; that is, UART0, UART1, etc.

2.3Pin Multiplexing

On the DM643x DMP extensive pin multiplexing is used to accommodate the largest number of peripheral functions in the smallest possible package. Pin multiplexing is controlled using a combination of hardware configuration at device reset and software programmable register settings. Refer to the device-specific data manual to determine how pin multiplexing affects the UART.

2.4Protocol Description

2.4.1Transmission

The UART transmitter section includes a transmitter hold register (THR) and a transmitter shift register (TSR). When the UART is in the FIFO mode, THR is a 16-byte FIFO. Transmitter section control is a function of the UART line control register (LCR). Based on the settings chosen in LCR, the UART transmitter sends the following to the receiving device:

1 START bit

5, 6, 7, or 8 data bits

1 PARITY bit (optional)

1, 1.5, or 2 STOP bits

2.4.2Reception

The UART receiver section includes a receiver shift register (RSR) and a receiver buffer register (RBR). When the UART is in the FIFO mode, RBR is a 16-byte FIFO. Receiver section control is a function of the UART line control register (LCR). Based on the settings chosen in LCR, the UART receiver accepts the following from the transmitting device:

1 START bit

5, 6, 7, or 8 data bits

1 PARITY bit (optional)

1 STOP bit (any other STOP bits transferred with the above data are not detected)

12

Universal Asynchronous Receiver/Transmitter (UART)

SPRU997C –December 2009

 

 

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Texas Instruments TMS320DM643X DMP manual Signal Descriptions, Pin Multiplexing, Protocol Description