Philips Semiconductors

Product specification

SC28L91

3.3V–5.0V Universal Asynchronous

Receiver/Transmitter (UART)

2000 Sep 22

26

CSR CLOCK SELECT REGISTER

Addr

CSR (7:4)

CSR (3:0)

CSR

RECEIVER CLOCK SELECT

TRANSMITTER CLOCK SELECT

0x01

See Text and table 5

See Text and table 5

MR0[0] = 0 (Normal Mode)

MR0[0] = 1 (Extended Mode I)

MR0[2] = 1 (Extended Mode II)

CSRA[7:4]

ACR[7] = 0

ACR[7] = 1

ACR[7] = 0

ACR[7] = 1

ACR[7] = 0

ACR[7] = 1

0000

50

75

300

450

4,800

7,200

0001

110

110

110

110

880

880

0010

134.5

134.5

134.5

134.5

1,076

1,076

0011

200

150

1200

900

19.2K

14.4K

0100

300

300

1800

1800

28.8K

28.8K

0101

600

600

3600

3600

57.6K

57.6K

0110

1,200

1,200

7200

7,200

115.2K

115.2K

0111

1,050

2,000

1,050

2,000

1,050

2,000

1000

2,400

2,400

14.4K

14.4K

57.6K

57.6K

1001

4,800

4,800

28.8K

28.8K

4,800

4,800

1010

7,200

1,800

7,200

1,800

57.6K

14.4K

1011

9,600

9,600

57.6K

57.6K

9,600

9,600

1100

38.4K

19.2K

230.4K

115.2K

38.4K

19.2K

1101

Timer

Timer

Timer

Timer

Timer

Timer

1110

IP4–16X

IP4–16X

IP4–16X

IP4–16X

IP4–16X

IP4–16X

1111

IP4–1X

IP4–1X

IP4–1X

IP4–1X

IP4–1X

IP4–1X

NOTE:

1. The receiver clock is always a 16X clock except for CSR[7:4] = 1111. CSR[3:0]— Transmitter Clock Select. This field selects the baud rate

clock for the transmitter.

The field definition is as shown in Table 5, except as follows:

CSR[3:0]

1110

IP3 –16X

1111

IP3 –1X

The transmitter clock is always a 16X clock except for CSR[3:0] = 1111.

Table 6. Bit rate generator characteristics for Crystal or Clock = 3.6864MHz

NORMAL RATE (BAUD)

ACTUAL 16X CLOCK (KHz)

ERROR (%)

50

0.8

0

75

1.2

0

110

1.759

–0.069

134.5

2.153

0.059

150

2.4

0

200

3.2

0

300

4.8

0

600

9.6

0

1050

16.756

–0.260

1200

19.2

0

1800

28.8

0

2000

32.056

0.175

2400

38.4

0

4800

76.8

0

7200

115.2

0

9600

153.6

0

19.2K

307.2

0

38.4K

614.4

0

NOTE:

Duty cycle of 16X clock is 50%

1%