LS_Universal asynchronous receiver/transmitter (UART)
RM0082
602/844
Doc ID 018672 Rev 1
Note:
To enable transmission, both TXE (bit 8) and UARTEN (bit 0) must be set. Similarly, to
enable reception, both RXE (bit 9) and UARTEN must be set.
Note:
The UART CSRs should be programmed as follows:
- disable the UART (clearing the UARTEN bit in UARTCR register),
- wait for the end of transmission or reception of the current character,
- flush the Transmit FIFO by disabling the FEN bit in the UARTLCR_H register,
- program the UART CSRs (if required)
- enable the UART (setting the UARTEN bit in UARTCR register).
27.4.8 UARTIFLS
register
The UARTIFLS (Interrupt FIFO level select) is a 16 bit RW register which defines the FIFO
level at which the UARTTXINTR and UARTRXINTR interrupts are triggered (
The interrupts are generated based on a transition through a level rather than being based
on the level, that is, when the fill level progresses through the trigger level. The UARTIFLS
bit assignments are given in
.
[08]
TXE
1’h1
Transmit enable.
Setting this bit the transmit section of UART is enabled. Data
transmission occurs for UART signals. When the UART is
disabled in the middle of transmission, it completes the current
character before stopping.
[07]
LBE
1’h0
Loop back enable.
Used together with test registers only.
[06:01] Reserved -
Read: as zero. Write: should be zero.
[00]
UARTEN
1’h0
UART enable.
Setting this bit, the UART is enabled. Data transmission and
reception occurs for UART signals. When the UART is disabled in
the middle of transmission or reception, it completes the current
character before stopping.
Table 530.
UARTCR register bit assignments (continued)
Bit
Name
Reset value Description
Table 531.
UARTIFLS register bit assignments
Bit
Name
Reset value Description
[15:06]
Reserved
-
Read: as zero. Write: should be zero.