Texas Instruments TMS320DM643X DMP User Manual
Page 12
Peripheral Architecture
www.ti.com
2.2
Signal Descriptions
The UARTs utilize a minimal number of signal connections to interface with external devices. The UART
signal descriptions are included in
. 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.
2.3
Pin 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.
2.4
Protocol Description
2.4.1
Transmission
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
2.4.2
Reception
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
Copyright © 2009, Texas Instruments Incorporated