PIC24HJXXXGPX06/X08/X10
DS70175H-page 172
2009 Microchip Technology Inc.
REGISTER 18-2:
UxSTA: UARTx STATUS AND CONTROL REGISTER
R/W-0
U-0
R/W-0 HC
R/W-0
R-0
R-1
UTXISEL1
UTXINV
UTXISEL0
—
UTXBRK
UTXEN(1)
UTXBF
TRMT
bit 15
bit 8
R/W-0
R-1
R-0
R/C-0
R-0
URXISEL<1:0>
ADDEN
RIDLE
PERR
FERR
OERR
URXDA
bit 7
bit 0
Legend:
HC = Hardware cleared
C = Clear only bit
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
bit 15,13
UTXISEL<1:0>: Transmission Interrupt Mode Selection bits
11
= Reserved; do not use
10
= Interrupt when a character is transferred to the Transmit Shift Register, and as a result, the
transmit buffer becomes empty
01
= Interrupt when the last character is shifted out of the Transmit Shift Register; all transmit
operations are completed
00
= Interrupt when a character is transferred to the Transmit Shift Register (this implies there is
at least one character open in the transmit buffer)
bit 14
UTXINV: Transmit Polarity Inversion bit
If IREN = 0:
1
= UxTX Idle state is ‘0’
0
= UxTX Idle state is ‘1’
If IREN = 1:
1
= IrDA encoded UxTX Idle state is ‘1’
0
= IrDA encoded UxTX Idle state is ‘0’
bit 12
Unimplemented: Read as ‘0’
bit 11
UTXBRK: Transmit Break bit
1
= Send Sync Break on next transmission – Start bit, followed by twelve ‘0’ bits, followed by Stop bit;
cleared by hardware upon completion
0
= Sync Break transmission disabled or completed
bit 10
UTXEN: Transmit Enable bit(1)
1
= Transmit enabled, UxTX pin controlled by UARTx
0
= Transmit disabled, any pending transmission is aborted and buffer is reset. UxTX pin controlled
by port.
bit 9
UTXBF: Transmit Buffer Full Status bit (read-only)
1
= Transmit buffer is full
0
= Transmit buffer is not full, at least one more character can be written
bit 8
TRMT: Transmit Shift Register Empty bit (read-only)
1
= Transmit Shift Register is empty and transmit buffer is empty (the last transmission has completed)
0
= Transmit Shift Register is not empty, a transmission is in progress or queued
bit 7-6
URXISEL<1:0>: Receive Interrupt Mode Selection bits
11
= Interrupt is set on UxRSR transfer making the receive buffer full (i.e., has 4 data characters)
10
= Interrupt is set on UxRSR transfer making the receive buffer 3/4 full (i.e., has 3 data characters)
0x
= Interrupt is set when any character is received and transferred from the UxRSR to the receive
buffer. Receive buffer has one or more characters.
Note 1: Refer to Section 17. “UART” (DS70232) in the “PIC24H Family Reference Manual” for information on
enabling the UART module for transmit operation.