W83877ATG Nuvoton Technology Corporation of America, W83877ATG Datasheet - Page 47

• Manufacturer Part Number: W83877ATG
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83877ATG

• Lead Free Status / RoHS Status: Supplier Unconfirmed

TABLE 3-2 WORD LENGTH DEFINITION
6.2.2
This 8-bit register provides information about the status of the data transfer during communication.
Bit 7: RFEI. In 16450 mode, this bit is always set to a logic 0. In 16550 mode, this bit is set to a logic 1
Bit 6: TSRE. In 16450 mode, when TBR and TSR are both empty, this bit will be set to a logical 1. In
Bit 5: TBRE. In 16450 mode, when a data character is transferred from TBR to TSR, this bit will be set
Bit 4: SBD. This bit is set to a logical 1 to indicate that received data are kept in silent state for a full
when there is at least one parity bit error, but no stop bit error or silent byte detected in the
FIFO. In 16550 mode, this bit is cleared by reading from the USR if there are no remaining
errors left in the FIFO.
16550 mode, if the transmit FIFO and TSR are both empty, it will be set to a logical 1. Other
than in these two cases, this bit will be reset to a logical 0.
to a logical 1. If ETREI of ICR is a logical 1, an interrupt will be generated to notify the CPU to
write the next data. In 16550 mode, this bit will be set to a logical 1 when the transmit FIFO is
empty. It will be reset to a logical 0 when the CPU writes data into TBR or FIFO.
word time, including start bit, data bits, parity bit, and stop bits. In 16550 mode, it indicates the
same condition for the data on top of the FIFO. When the CPU reads USR, it will clear this bit
to a logical 0.
UART Status Register (USR) (Read/Write)
DLS1
0
0
1
1
7
6
5
4
3
DLS0
2
0
1
0
1
1
0
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Overrun error (OER)
Parity bit error (PBER)
No stop bit error (NSER)
Silent byte detected (SBD)
Transmitter Buffer Register empty (TBRE)
Transmitter Shift Register empty (TSRE)
RBR Data ready (RDR)
RX FIFO Error Indication (RFEI)
W83877ATF/W83877ATG
DATA LENGTH
5 bits
6 bits
7 bits
8 bits