UART0

Instance: UART0
Component: UART
Base address: 0x40001000


Universal Asynchronous Receiver/Transmitter (UART) interface

TOP:UART0 Register Summary

Register Name

Type

Register Width (Bits)

Register Reset

Address Offset

Physical Address

DR

RW

32

0x0000 0XXX

0x0000 0000

0x4000 1000

RSR

RO

32

0x0000 0000

0x0000 0004

0x4000 1004

ECR

WO

32

0x0000 0000

0x0000 0004

0x4000 1004

FR

RO

32

0b0000 0000 0000 0000 0000 0000 1001 000X

0x0000 0018

0x4000 1018

IBRD

RW

32

0x0000 0000

0x0000 0024

0x4000 1024

FBRD

RW

32

0x0000 0000

0x0000 0028

0x4000 1028

LCRH

RW

32

0x0000 0000

0x0000 002C

0x4000 102C

CTL

RW

32

0x0000 0300

0x0000 0030

0x4000 1030

IFLS

RW

32

0x0000 0012

0x0000 0034

0x4000 1034

IMSC

RW

32

0x0000 0000

0x0000 0038

0x4000 1038

RIS

RO

32

0b0000 0000 0000 0000 0000 0000 0000 11X1

0x0000 003C

0x4000 103C

MIS

RO

32

0x0000 0000

0x0000 0040

0x4000 1040

ICR

WO

32

0x0000 XXXX

0x0000 0044

0x4000 1044

DMACTL

RW

32

0x0000 0000

0x0000 0048

0x4000 1048

TOP:UART0 Register Descriptions

TOP:UART0:DR

Address Offset 0x0000 0000
Physical Address 0x4000 1000 Instance 0x4000 1000
Description Data
For words to be transmitted:
- if the FIFOs are enabled (LCRH.FEN = 1), data written to this location is pushed onto the transmit FIFO
- if the FIFOs are not enabled (LCRH.FEN = 0), data is stored in the transmitter holding register (the bottom word of the transmit FIFO).
The write operation initiates transmission from the UART. The data is prefixed with a start bit, appended with the appropriate parity bit (if parity is enabled), and a stop bit.
The resultant word is then transmitted.
For received words:
- if the FIFOs are enabled (LCRH.FEN = 1), the data byte and the 4-bit status (break, frame, parity, and overrun) is pushed onto the 12-bit wide receive FIFO
- if the FIFOs are not enabled (LCRH.FEN = 0), the data byte and status are stored in the receiving holding register (the bottom word of the receive FIFO).
The received data byte is read by performing reads from this register along with the corresponding status information. The status information can also be read by a read of the RSR register.
Type RW
Bits Field Name Description Type Reset
31:12 RESERVED Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0x0 0000
11 OE UART Overrun Error:
This bit is set to 1 if data is received and the receive FIFO is already full. The FIFO contents remain valid because no more data is written when the FIFO is full, , only the contents of the shift register are overwritten.
This is cleared to 0 once there is an empty space in the FIFO and a new character can be written to it.
RO X
10 BE UART Break Error:
This bit is set to 1 if a break condition was detected, indicating that the received data input (UARTRXD input pin) was held LOW for longer than a full-word transmission time (defined as start, data, parity and stop bits).
In FIFO mode, this error is associated with the character at the top of the FIFO (i.e., the oldest received data character since last read). When a break occurs, a 0 character is loaded into the FIFO. The next character is enabled after the receive data input (UARTRXD input pin) goes to a 1 (marking state), and the next valid start bit is received.
RO X
9 PE UART Parity Error:
When set to 1, it indicates that the parity of the received data character does not match the parity that the LCRH.EPS and LCRH.SPS select.
In FIFO mode, this error is associated with the character at the top of the FIFO (i.e., the oldest received data character since last read).
RO X
8 FE UART Framing Error:
When set to 1, it indicates that the received character did not have a valid stop bit (a valid stop bit is 1).
In FIFO mode, this error is associated with the character at the top of the FIFO (i.e., the oldest received data character since last read).
RO X
7:0 DATA Data transmitted or received:
On writes, the transmit data character is pushed into the FIFO.
On reads, the oldest received data character since the last read is returned.
RW 0xXX

TOP:UART0:RSR

Address Offset 0x0000 0004
Physical Address 0x4000 1004 Instance 0x4000 1004
Description Status
This register is mapped to the same address as ECR register. Reads from this address are associated with RSR register and return the receive status. Writes to this address are associated with ECR register and clear the receive status flags (framing, parity, break, and overrun errors).
If the status is read from this register, then the status information for break, framing and parity corresponds to the data character read from the Data Register, DR prior to reading the RSR. The status information for overrun is set immediately when an overrun condition occurs.
Type RO
Bits Field Name Description Type Reset
31:4 RESERVED Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0x000 0000
3 OE UART Overrun Error:
This bit is set to 1 if data is received and the receive FIFO is already full. The FIFO contents remain valid because no more data is written when the FIFO is full, , only the contents of the shift register are overwritten.
This is cleared to 0 once there is an empty space in the FIFO and a new character can be written to it.
RO 0
2 BE UART Break Error:
This bit is set to 1 if a break condition was detected, indicating that the received data input (UARTRXD input pin) was held LOW for longer than a full-word transmission time (defined as start, data, parity and stop bits).
When a break occurs, a 0 character is loaded into the FIFO. The next character is enabled after the receive data input (UARTRXD input pin) goes to a 1 (marking state), and the next valid start bit is received.
RO 0
1 PE UART Parity Error:
When set to 1, it indicates that the parity of the received data character does not match the parity that the LCRH.EPS and LCRH.SPS select.
RO 0
0 FE UART Framing Error:
When set to 1, it indicates that the received character did not have a valid stop bit (a valid stop bit is 1).
RO 0

TOP:UART0:ECR

Address Offset 0x0000 0004
Physical Address 0x4000 1004 Instance 0x4000 1004
Description Error Clear
This register is mapped to the same address as RSR register. Reads from this address are associated with RSR register and return the receive status. Writes to this address are associated with ECR register and clear the receive status flags (framing, parity, break, and overrun errors).
Type WO
Bits Field Name Description Type Reset
31:4 RESERVED Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. WO 0x000 0000
3 OE The framing (FE), parity (PE), break (BE) and overrun (OE) errors are cleared to 0 by any write to this register. WO 0
2 BE The framing (FE), parity (PE), break (BE) and overrun (OE) errors are cleared to 0 by any write to this register. WO 0
1 PE The framing (FE), parity (PE), break (BE) and overrun (OE) errors are cleared to 0 by any write to this register. WO 0
0 FE The framing (FE), parity (PE), break (BE) and overrun (OE) errors are cleared to 0 by any write to this register. WO 0

TOP:UART0:FR

Address Offset 0x0000 0018
Physical Address 0x4000 1018 Instance 0x4000 1018
Description Flag
Reads from this register return the UART flags.
Type RO
Bits Field Name Description Type Reset
31:8 RESERVED1 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0x00 0000
7 TXFE UART Transmit FIFO Empty:
The meaning of this bit depends on the state of LCRH.FEN .
- If the FIFO is disabled, this bit is set when the transmit holding register is empty.
- If the FIFO is enabled, this bit is set when the transmit FIFO is empty.
This bit does not indicate if there is data in the transmit shift register.
RO 1
6 RXFF UART Receive FIFO Full:
The meaning of this bit depends on the state of LCRH.FEN.
- If the FIFO is disabled, this bit is set when the receive holding register is full.
- If the FIFO is enabled, this bit is set when the receive FIFO is full.
RO 0
5 TXFF UART Transmit FIFO Full:
Transmit FIFO full. The meaning of this bit depends on the state of LCRH.FEN.
- If the FIFO is disabled, this bit is set when the transmit holding register is full.
- If the FIFO is enabled, this bit is set when the transmit FIFO is full.
RO 0
4 RXFE UART Receive FIFO Empty:
Receive FIFO empty. The meaning of this bit depends on the state of LCRH.FEN.
- If the FIFO is disabled, this bit is set when the receive holding register is empty.
- If the FIFO is enabled, this bit is set when the receive FIFO is empty.
RO 1
3 BUSY UART Busy:
If this bit is set to 1, the UART is busy transmitting data. This bit remains set until the complete byte, including all the stop bits, has been sent from the shift register.
This bit is set as soon as the transmit FIFO becomes non-empty, regardless of whether the UART is enabled or not.
RO 0
2:1 RESERVED0 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0b00
0 CTS Clear To Send:
This bit is the complement of the active-low UART CTS input pin.
That is, the bit is 1 when CTS input pin is LOW.
RO X

TOP:UART0:IBRD

Address Offset 0x0000 0024
Physical Address 0x4000 1024 Instance 0x4000 1024
Description Integer Baud-Rate Divisor
If this register is modified while trasmission or reception is on-going, the baudrate will not be updated until transmission or reception of the current character is complete.
Type RW
Bits Field Name Description Type Reset
31:16 RESERVED Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0x0000
15:0 DIVINT The integer baud rate divisor:
The baud rate divisor is calculated using the formula below:
Baud rate divisor = (UART reference clock frequency) / (16 * Baud rate)
Baud rate divisor must be minimum 1 and maximum 65535.
That is, DIVINT=0 does not give a valid baud rate.
Similarly, if DIVINT=0xFFFF, any non-zero values in FBRD.DIVFRAC will be illegal.
A valid value must be written to this field before the UART can be used for RX or TX operations.
RW 0x0000

TOP:UART0:FBRD

Address Offset 0x0000 0028
Physical Address 0x4000 1028 Instance 0x4000 1028
Description Fractional Baud-Rate Divisor
If this register is modified while trasmission or reception is on-going, the baudrate will not be updated until transmission or reception of the current character is complete.
Type RW
Bits Field Name Description Type Reset
31:6 RESERVED Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0b00 0000 0000 0000 0000 0000 0000
5:0 DIVFRAC Fractional Baud-Rate Divisor:
The baud rate divisor is calculated using the formula below:
Baud rate divisor = (UART reference clock frequency) / (16 * Baud rate)
Baud rate divisor must be minimum 1 and maximum 65535.
That is, IBRD.DIVINT=0 does not give a valid baud rate.
Similarly, if IBRD.DIVINT=0xFFFF, any non-zero values in DIVFRAC will be illegal.
A valid value must be written to this field before the UART can be used for RX or TX operations.
RW 0b00 0000

TOP:UART0:LCRH

Address Offset 0x0000 002C
Physical Address 0x4000 102C Instance 0x4000 102C
Description Line Control
Type RW
Bits Field Name Description Type Reset
31:8 RESERVED Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0x00 0000
7 SPS UART Stick Parity Select:

0: Stick parity is disabled
1: The parity bit is transmitted and checked as invert of EPS field (i.e. the parity bit is transmitted and checked as 1 when EPS = 0).

This bit has no effect when PEN disables parity checking and generation.
RW 0
6:5 WLEN UART Word Length:
These bits indicate the number of data bits transmitted or received in a frame.
Value ENUM Name Description
0x0 5 Word Length 5 bits
0x1 6 Word Length 6 bits
0x2 7 Word Length 7 bits
0x3 8 Word Length 8 bits
RW 0b00
4 FEN UART Enable FIFOs
Value ENUM Name Description
0x0 DIS FIFOs are disabled (character mode) that is, the FIFOs become 1-byte-deep holding registers.
0x1 EN Transmit and receive FIFO buffers are enabled (FIFO mode)
RW 0
3 STP2 UART Two Stop Bits Select:
If this bit is set to 1, two stop bits are transmitted at the end of the frame. The receive logic does not check for two stop bits being received.
RW 0
2 EPS UART Even Parity Select
Value ENUM Name Description
0x0 ODD Odd parity: The UART generates or checks for an odd number of 1s in the data and parity bits.
0x1 EVEN Even parity: The UART generates or checks for an even number of 1s in the data and parity bits.
RW 0
1 PEN UART Parity Enable
This bit controls generation and checking of parity bit.
Value ENUM Name Description
0x0 DIS Parity is disabled and no parity bit is added to the data frame
0x1 EN Parity checking and generation is enabled.
RW 0
0 BRK UART Send Break
If this bit is set to 1, a low-level is continually output on the UARTTXD output pin, after completing transmission of the current character. For the proper execution of the break command, the
software must set this bit for at least two complete frames. For normal use, this bit must be cleared to 0.
RW 0

TOP:UART0:CTL

Address Offset 0x0000 0030
Physical Address 0x4000 1030 Instance 0x4000 1030
Description Control
Type RW
Bits Field Name Description Type Reset
31:16 RESERVED16 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0x0000
15 CTSEN CTS hardware flow control enable
Value ENUM Name Description
0x0 DIS CTS hardware flow control disabled
0x1 EN CTS hardware flow control enabled
RW 0
14 RTSEN RTS hardware flow control enable
Value ENUM Name Description
0x0 DIS RTS hardware flow control disabled
0x1 EN RTS hardware flow control enabled
RW 0
13:12 RESERVED12 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0b00
11 RTS Request to Send
This bit is the complement of the active-low UART RTS output. That is, when the bit is programmed to a 1 then RTS output on the pins is LOW.
RW 0
10 RESERVED10 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0
9 RXE UART Receive Enable
If the UART is disabled in the middle of reception, it completes the current character before stopping.
Value ENUM Name Description
0x0 DIS UART Receive disabled
0x1 EN UART Receive enabled
RW 1
8 TXE UART Transmit Enable
If the UART is disabled in the middle of transmission, it completes the current character before stopping.
Value ENUM Name Description
0x0 DIS UART Transmit disabled
0x1 EN UART Transmit enabled
RW 1
7 LBE UART Loop Back Enable:
Enabling the loop-back mode connects the UARTTXD output from the UART to UARTRXD input of the UART.
Value ENUM Name Description
0x0 DIS Loop Back disabled
0x1 EN Loop Back enabled
RW 0
6:1 RESERVED1 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0b00 0000
0 UARTEN UART Enable
Value ENUM Name Description
0x0 DIS UART disabled
0x1 EN UART enabled
RW 0

TOP:UART0:IFLS

Address Offset 0x0000 0034
Physical Address 0x4000 1034 Instance 0x4000 1034
Description Interrupt FIFO Level Select
Type RW
Bits Field Name Description Type Reset
31:6 RESERVED Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0b00 0000 0000 0000 0000 0000 0000
5:3 RXSEL Receive interrupt FIFO level select:
This field sets the trigger points for the receive interrupt. Values 0b101-0b111 are reserved.
Value ENUM Name Description
0x0 1_8 Receive FIFO becomes >= 1/8 full
0x1 2_8 Receive FIFO becomes >= 1/4 full
0x2 4_8 Receive FIFO becomes >= 1/2 full
0x3 6_8 Receive FIFO becomes >= 3/4 full
0x4 7_8 Receive FIFO becomes >= 7/8 full
RW 0b010
2:0 TXSEL Transmit interrupt FIFO level select:
This field sets the trigger points for the transmit interrupt. Values 0b101-0b111 are reserved.
Value ENUM Name Description
0x0 1_8 Transmit FIFO becomes <= 1/8 full
0x1 2_8 Transmit FIFO becomes <= 1/4 full
0x2 4_8 Transmit FIFO becomes <= 1/2 full
0x3 6_8 Transmit FIFO becomes <= 3/4 full
0x4 7_8 Transmit FIFO becomes <= 7/8 full
RW 0b010

TOP:UART0:IMSC

Address Offset 0x0000 0038
Physical Address 0x4000 1038 Instance 0x4000 1038
Description Interrupt Mask Set/Clear
Type RW
Bits Field Name Description Type Reset
31:11 RESERVED11 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0b0 0000 0000 0000 0000 0000
10 OEIM Overrun error interrupt mask. A read returns the current mask for UART's overrun error interrupt. On a write of 1, the mask of the overrun error interrupt is set which means the interrupt state will be reflected in MIS.OEMIS. A write of 0 clears the mask which means MIS.OEMIS will not reflect the interrupt. RW 0
9 BEIM Break error interrupt mask. A read returns the current mask for UART's break error interrupt. On a write of 1, the mask of the overrun error interrupt is set which means the interrupt state will be reflected in MIS.BEMIS. A write of 0 clears the mask which means MIS.BEMIS will not reflect the interrupt. RW 0
8 PEIM Parity error interrupt mask. A read returns the current mask for UART's parity error interrupt. On a write of 1, the mask of the overrun error interrupt is set which means the interrupt state will be reflected in MIS.PEMIS. A write of 0 clears the mask which means MIS.PEMIS will not reflect the interrupt. RW 0
7 FEIM Framing error interrupt mask. A read returns the current mask for UART's framing error interrupt. On a write of 1, the mask of the overrun error interrupt is set which means the interrupt state will be reflected in MIS.FEMIS. A write of 0 clears the mask which means MIS.FEMIS will not reflect the interrupt. RW 0
6 RTIM Receive timeout interrupt mask. A read returns the current mask for UART's receive timeout interrupt. On a write of 1, the mask of the overrun error interrupt is set which means the interrupt state will be reflected in MIS.RTMIS. A write of 0 clears the mask which means this bitfield will not reflect the interrupt.
The raw interrupt for receive timeout RIS.RTRIS cannot be set unless the mask is set (RTIM = 1). This is because the mask acts as an enable for power saving. That is, the same status can be read from MIS.RTMIS and RIS.RTRIS.
RW 0
5 TXIM Transmit interrupt mask. A read returns the current mask for UART's transmit interrupt. On a write of 1, the mask of the overrun error interrupt is set which means the interrupt state will be reflected in MIS.TXMIS. A write of 0 clears the mask which means MIS.TXMIS will not reflect the interrupt. RW 0
4 RXIM Receive interrupt mask. A read returns the current mask for UART's receive interrupt. On a write of 1, the mask of the overrun error interrupt is set which means the interrupt state will be reflected in MIS.RXMIS. A write of 0 clears the mask which means MIS.RXMIS will not reflect the interrupt. RW 0
3:2 RESERVED2 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0b00
1 CTSMIM Clear to Send (CTS) modem interrupt mask. A read returns the current mask for UART's clear to send interrupt. On a write of 1, the mask of the overrun error interrupt is set which means the interrupt state will be reflected in MIS.CTSMMIS. A write of 0 clears the mask which means MIS.CTSMMIS will not reflect the interrupt. RW 0
0 RESERVED0 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0

TOP:UART0:RIS

Address Offset 0x0000 003C
Physical Address 0x4000 103C Instance 0x4000 103C
Description Raw Interrupt Status
Type RO
Bits Field Name Description Type Reset
31:11 RESERVED11 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0b0 0000 0000 0000 0000 0000
10 OERIS Overrun error interrupt status:
This field returns the raw interrupt state of UART's overrun error interrupt. Overrun error occurs if data is received and the receive FIFO is full.
RO 0
9 BERIS Break error interrupt status:
This field returns the raw interrupt state of UART's break error interrupt. Break error is set when a break condition is detected, indicating that the received data input (UARTRXD input pin) was held LOW for longer than a full-word transmission time (defined as start, data, parity and stop bits).
RO 0
8 PERIS Parity error interrupt status:
This field returns the raw interrupt state of UART's parity error interrupt. Parity error is set if the parity of the received data character does not match the parity that the LCRH.EPS and LCRH.SPS select.
RO 0
7 FERIS Framing error interrupt status:
This field returns the raw interrupt state of UART's framing error interrupt. Framing error is set if the received character does not have a valid stop bit (a valid stop bit is 1).
RO 0
6 RTRIS Receive timeout interrupt status:
This field returns the raw interrupt state of UART's receive timeout interrupt. The receive timeout interrupt is asserted when the receive FIFO is not empty, and no more data is received during a 32-bit period. The receive timeout interrupt is cleared either when the FIFO becomes empty through reading all the data, or when a 1 is written to ICR.RTIC.
The raw interrupt for receive timeout cannot be set unless the mask is set (IMSC.RTIM = 1). This is because the mask acts as an enable for power saving. That is, the same status can be read from MIS.RTMIS and RTRIS.
RO 0
5 TXRIS Transmit interrupt status:
This field returns the raw interrupt state of UART's transmit interrupt.
When FIFOs are enabled (LCRH.FEN = 1), the transmit interrupt is asserted if the number of bytes in transmit FIFO is equal to or lower than the programmed trigger level (IFLS.TXSEL). The transmit interrupt is cleared by writing data to the transmit FIFO until it becomes greater than the trigger level, or by clearing the interrupt through ICR.TXIC.
When FIFOs are disabled (LCRH.FEN = 0), that is they have a depth of one location, the transmit interrupt is asserted if there is no data present in the transmitters single location. It is cleared by performing a single write to the transmit FIFO, or by clearing the interrupt through ICR.TXIC.
RO 0
4 RXRIS Receive interrupt status:
This field returns the raw interrupt state of UART's receive interrupt.
When FIFOs are enabled (LCRH.FEN = 1), the receive interrupt is asserted if the receive FIFO reaches the programmed trigger
level (IFLS.RXSEL). The receive interrupt is cleared by reading data from the receive FIFO until it becomes less than the trigger level, or by clearing the interrupt through ICR.RXIC.
When FIFOs are disabled (LCRH.FEN = 0), that is they have a depth of one location, the receive interrupt is asserted if data is received
thereby filling the location. The receive interrupt is cleared by performing a single read of the receive FIFO, or by clearing the interrupt through ICR.RXIC.
RO 0
3:2 RESERVED2 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0b11
1 CTSRMIS Clear to Send (CTS) modem interrupt status:
This field returns the raw interrupt state of UART's clear to send interrupt.
RO X
0 RESERVED0 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 1

TOP:UART0:MIS

Address Offset 0x0000 0040
Physical Address 0x4000 1040 Instance 0x4000 1040
Description Masked Interrupt Status
Type RO
Bits Field Name Description Type Reset
31:11 RESERVED11 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0b0 0000 0000 0000 0000 0000
10 OEMIS Overrun error masked interrupt status:
This field returns the masked interrupt state of the overrun interrupt which is the AND product of raw interrupt state RIS.OERIS and the mask setting IMSC.OEIM.
RO 0
9 BEMIS Break error masked interrupt status:
This field returns the masked interrupt state of the break error interrupt which is the AND product of raw interrupt state RIS.BERIS and the mask setting IMSC.BEIM.
RO 0
8 PEMIS Parity error masked interrupt status:
This field returns the masked interrupt state of the parity error interrupt which is the AND product of raw interrupt state RIS.PERIS and the mask setting IMSC.PEIM.
RO 0
7 FEMIS Framing error masked interrupt status: Returns the masked interrupt state of the framing error interrupt which is the AND product of raw interrupt state RIS.FERIS and the mask setting IMSC.FEIM. RO 0
6 RTMIS Receive timeout masked interrupt status:
Returns the masked interrupt state of the receive timeout interrupt.
The raw interrupt for receive timeout cannot be set unless the mask is set (IMSC.RTIM = 1). This is because the mask acts as an enable for power saving. That is, the same status can be read from RTMIS and RIS.RTRIS.
RO 0
5 TXMIS Transmit masked interrupt status:
This field returns the masked interrupt state of the transmit interrupt which is the AND product of raw interrupt state RIS.TXRIS and the mask setting IMSC.TXIM.
RO 0
4 RXMIS Receive masked interrupt status:
This field returns the masked interrupt state of the receive interrupt which is the AND product of raw interrupt state RIS.RXRIS and the mask setting IMSC.RXIM.
RO 0
3:2 RESERVED2 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0b00
1 CTSMMIS Clear to Send (CTS) modem masked interrupt status:
This field returns the masked interrupt state of the clear to send interrupt which is the AND product of raw interrupt state RIS.CTSRMIS and the mask setting IMSC.CTSMIM.
RO 0
0 RESERVED0 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RO 0

TOP:UART0:ICR

Address Offset 0x0000 0044
Physical Address 0x4000 1044 Instance 0x4000 1044
Description Interrupt Clear
On a write of 1, the corresponding interrupt is cleared. A write of 0 has no effect.
Type WO
Bits Field Name Description Type Reset
31:11 RESERVED11 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. WO 0b0 0000 0000 0000 000X XXXX
10 OEIC Overrun error interrupt clear:
Writing 1 to this field clears the overrun error interrupt (RIS.OERIS). Writing 0 has no effect.
WO X
9 BEIC Break error interrupt clear:
Writing 1 to this field clears the break error interrupt (RIS.BERIS). Writing 0 has no effect.
WO X
8 PEIC Parity error interrupt clear:
Writing 1 to this field clears the parity error interrupt (RIS.PERIS). Writing 0 has no effect.
WO X
7 FEIC Framing error interrupt clear:
Writing 1 to this field clears the framing error interrupt (RIS.FERIS). Writing 0 has no effect.
WO X
6 RTIC Receive timeout interrupt clear:
Writing 1 to this field clears the receive timeout interrupt (RIS.RTRIS). Writing 0 has no effect.
WO X
5 TXIC Transmit interrupt clear:
Writing 1 to this field clears the transmit interrupt (RIS.TXRIS). Writing 0 has no effect.
WO X
4 RXIC Receive interrupt clear:
Writing 1 to this field clears the receive interrupt (RIS.RXRIS). Writing 0 has no effect.
WO X
3:2 RESERVED2 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. Write 0 WO 0xX
1 CTSMIC Clear to Send (CTS) modem interrupt clear:
Writing 1 to this field clears the clear to send interrupt (RIS.CTSRMIS). Writing 0 has no effect.
WO X
0 RESERVED0 Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. Write 0. WO X

TOP:UART0:DMACTL

Address Offset 0x0000 0048
Physical Address 0x4000 1048 Instance 0x4000 1048
Description DMA Control
Type RW
Bits Field Name Description Type Reset
31:3 RESERVED Software should not rely on the value of a reserved. Writing any other value than the reset value may result in undefined behavior. RW 0b0 0000 0000 0000 0000 0000 0000 0000
2 DMAONERR DMA on error. If this bit is set to 1, the DMA receive request outputs (for single and burst requests) are disabled when the UART error interrupt is asserted (more specifically if any of the error interrupts RIS.PERIS, RIS.BERIS, RIS.FERIS or RIS.OERIS are asserted). RW 0
1 TXDMAE Transmit DMA enable. If this bit is set to 1, DMA for the transmit FIFO is enabled. RW 0
0 RXDMAE Receive DMA enable. If this bit is set to 1, DMA for the receive FIFO is enabled. RW 0