CS5535 datasheet(386/555 Pages) NSC

386 / 555 page

www.national.com

386

Revision 0.8

UART/IR Controller Register Descriptions (Continued)

5.12.5.5

TX_FIFO Current Level Register (TXFLV)

TXFLV returns the number of bytes in the TX_FIFO.

5:4

PRESL[1:0]

Prescaler Select. The prescaler divides the 24 MHz input clock frequency to provide the

clock for the baud generator.

00: 13 (Default)

01: 1.625

10: Reserved

11: 1.0

3:2

RF_SIZ[1:0]

RX_FIFO Levels Select. These bits select the number of levels for the RX_FIFO. They

are effective only when the FIFOs are enabled. (FCR bit 0 = 1.)

00: 16 (Default)

01: 32

1x: Reserved

1:0

TF_SIZ[1:0]

TX_FIFO Levels Select. These bits select the number of levels for the TX_FIFO. They

are effective only when the FIFOs are enabled. (FCR bit 0 = 1.)

00: 16 (Default)

01: 32

1x: Reserved

I/O Offset

06h

Type

Reset Value

00h

TXFLV Register Map

RSVD

TFL[5:0]

TXFLV Bit Descriptions

Bit

Name

Description

7:6

RSVD

Reserved. Returns 0.

5:0

TFL[5:0]

Number of Bytes in TX_FIFO. These bits specify the number of bytes in the TX_FIFO.

Note:

The contents of TXFLV and RXFLV are not frozen during CPU reads. Therefore,

invalid data could be returned if the CPU reads these registers during normal

transmitter and receiver operation. To obtain correct data, the software should

perform three consecutive reads and then take the data from the second read if

the first and second reads yield the same result. It can also be taken from the

third read if the first and second reads yield different results.

EXCR2 Bit Descriptions (Continued)

Bit

Name

Description

CS5535 Datasheet(PDF) 386 Page - National Semiconductor (TI)

CS5535 Datasheet(HTML) 386 Page - National Semiconductor (TI)

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL