USR

         UART Status register.

Module Instance	Base Address	Register Address
`i_uart_0_uart_address_block`	`0xFFC02000`	`0xFFC0207C`
`i_uart_1_uart_address_block`	`0xFFC02100`	`0xFFC0217C`

Size: 32

Offset: 0x7C

Access: RO

Important: The value of a reserved bit must be maintained in software. When you modify registers containing reserved bit fields, you must use a read-modify-write operation to preserve state and prevent indeterminate system behavior.

Bit Fields
31	30	29	28	27	26	25	24	23	22	21	20	19	18	17	16
`RSVD_USR_31to5` `RO 0x0`
15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
`RSVD_USR_31to5` `RO 0x0`											`RFF` `RO 0x0`	`RFNE` `RO 0x0`	`TFE` `RO 0x1`	`TFNF` `RO 0x1`	`RSVD_BUSY` `RO 0x0`

USR Fields

Bit

Name

Description

Access

Reset

31:5

RSVD_USR_31to5

Reserved bits [31:5] - Read Only

RO

0x0

RFF

Receive FIFO Full.
This bit is only valid when FIFO_STAT == YES. This is used to indicate that the
receive FIFO is completely full. That is:
0 = Receive FIFO not full
1 = Receive FIFO Full
This bit is cleared when the RX FIFO is no longer full.

Value	Description
0x0	Receive FIFO not full
0x1	Receive FIFO full

RO

0x0

RFNE

Receive FIFO Not Empty.
This bit is only valid when FIFO_STAT == YES. This is used to indicate that the
receive FIFO contains one or more entries.
0 = Receive FIFO is empty
1 = Receive FIFO is not empty
This bit is cleared when the RX FIFO is empty.

Value	Description
0x0	Receive FIFO is empty
0x1	Receive FIFO is not empty

RO

0x0

TFE

Transmit FIFO Empty.
This bit is only valid when FIFO_STAT == YES. This is used to indicate that the
transmit FIFO is completely empty.
0 = Transmit FIFO is not empty
1 = Transmit FIFO is empty
This bit is cleared when the TX FIFO is no longer empty.

Value	Description
0x0	Transmit FIFO is not empty
0x1	Transmit FIFO is empty

RO

0x1

TFNF

Transmit FIFO Not Full.
This bit is only valid when FIFO_STAT == YES. This is used to indicate that the
transmit FIFO in not full.
0 = Transmit FIFO is full
1 = Transmit FIFO is not full
This bit is cleared when the TX FIFO is full.

Value	Description
0x0	Transmit FIFO is full
0x1	Transmit FIFO is not full

RO

0x1

RSVD_BUSY

UART Busy.
This bit is only valid when UART_16550_COMPATIBLE == NO. This indicates that a serial
transfer is in progress, when cleared indicates that the DW_apb_uart is idle or inactive.
0 - DW_apb_uart is idle or inactive
1 - DW_apb_uart is busy (actively transferring data)
Note that it is possible for the UART Busy bit to be cleared even though a new
character may have been sent from another device. That is, if the DW_apb_uart
has no data in the THR and RBR and there is no transmission in progress and a start
bit of a new character has just reached the DW_apb_uart. This is due to the fact
that a valid start is not seen until the middle of the bit period and this duration
is dependent on the baud divisor that has been programmed. If a second system clock
has been implemented (CLOCK_MODE == Enabled) the assertion of this bit will also be
delayed by several cycles of the slower clock.

Value	Description
0x0	DW_apb_uart is idle or inactive
0x1	DW_apb_uart is busy (actively transferring data)

RO

0x0