RM0082
LS_Universal asynchronous receiver/transmitter (UART)
Doc ID 018672 Rev 1
601/844
Note:
Baud rate and line control registers (UARTIBRD, UARTFBRD and UARTLCR_H) must not
be changed:
- when UART is enabled,
- when completing a transmission or a reception when it has programmed to become
disabled.
Moreover, the FIFOs integrity is not guaranteed under the following conditions:
- after the BRK bit (in UARTLCR_H register) has been initiated,
- if the software disables the UART in the middle of a transmission with data in the FIFO and
then re-enables it.
27.4.7 UARTCR
register
The UARTCR (control) is a 16 bit RW register which allows to control the UART. The
UARTCR bit assignments are given in
1‘b1
1‘b0
1‘b1
1
1‘b1
1‘b1
1‘b1
0
Table 529.
Truth table for SPS, EPS and PEN bits (continued)
Pen
Eps
Sps
Parity bit
Table 530.
UARTCR register bit assignments
Bit
Name
Reset value Description
[15]
CTSEn
1’h0
CTS hardware flow control enable.
Setting this bit, the CTS hardware flow control is enabled and data
is only transmitted when
nUARTCTS
signal is asserted.
[14]
RTSEn
1’h0
RTS hardware flow control enable.
Setting this bit, the RTS hardware flow control is enabled and data
is only requested when there is space in the Receive FIFO.
[13]
Out2
1’h0
Output.
This bit is the complement of UART Out2 (
nUARTOut2
) modem
status output (
). Setting this bit, this output is 1‘b0.
For DTE this can be used as Ring Indicator (RI).
[12]
Out1
1’h0
Out1.
This bit is the complement of UART Out1 (
nUARTOut1
) modem
status output (
). Setting this bit, this output is 1‘b0.
For DTE this can be used as Data Carrier Detect (DCD).
[11]
RTS
1’h0
Request to send.
This bit is the complement of UART RTS (
nUARTRTS
) modem
status output (
). Setting this bit, this output is 1‘b0.
[10]
DTR
1’h0
Data transmit ready.
This bit is the complement of UART DTR (nUARTDTR) modem
status output (
). Setting this bit, this output is 1‘b0.
[09]
RXE
1’h1
Receive enable.
Setting this bit the receive section of UART is enabled. Data
reception occurs for UART signals. When the UART is disabled in
the middle of reception, it completes the current character before
stopping.