Table 17-15. lsr bit definitions (sheet 1 of 3) – Intel PXA26X User Manual

Page 608

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17-24

Intel® PXA26x Processor Family Developer’s Manual

Hardware UART

See

Section 17.4.2.3, “FIFO DMA Mode Operation”

for details on using the DMA to receive data.

Table 17-15.

LSR Bit Definitions (Sheet 1 of 3)

Physical Address

0x4160_0014

Line Status Reg. (LSR)

PXA26x Processor Family Hardware

UART

User

Settings

Bit

31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9

8

7

6

5

4

3

2

1

0

Reserved

FIFO

E

TEM

T

T

DRQ

BI

FE

PE

OE

DR

Reset

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

?

0

1

1

0

0

0

0

0

Bits

Access

Name

Description

31:8

N/A

Reserved – Read as unknown and must be written as zero.

7

R

FIFOE

FIFO ERROR STATUS:

In non-FIFO mode, this bit is 0. In FIFO Mode, FIFOE is set to 1 when there
is at least one parity error, framing error, or break indication for any of the
characters in the FIFO. A processor read to the LSR does not reset this bit.
FIFOE is reset when all erroneous characters have been read from the
FIFO. If DMA requests are enabled (IER bit 7 is set to 1) and FIFOE is set
to 1, the error interrupt is generated and no receive DMA request is
generated even when the receive FIFO reaches the trigger threshold. Once
the errors have been cleared by reading the FIFO, DMA requests are re-
enabled automatically. If DMA requests are not enabled (IER bit7 is set to
0), FIFOE set to 1 does not generate an error interrupt.

0 – No FIFO or no errors in receiver FIFO

1 – At least one character in receiver FIFO has errors

6

R

TEMT

TRANSMITTER EMPTY:

Set when the Transmit Holding Register and the Transmitter Shift Register
are both empty. It is cleared when either the Transmit Holding Register or
the Transmitter Shift Register contains a data character. In FIFO mode,
TEMT is set when the transmitter FIFO and the Transmit Shift Register are
both empty.

0 – There is data in the Transmit Shift Register, the Transmit Holding

Register, or the FIFO

1 – All the data in the transmitter has been shifted out

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