XC888LM datasheet(94/144 Pages) INFINEON

94 / 144 page

XC886/888CLM

Functional Description

Data Sheet

V0.9, 2006-12

The following formulas calculate the final baud rate without and with the fractional divider

respectively:

(3.5)

(3.6)

The maximum baud rate that can be generated is limited to

PCLK/32. Hence, for a module

clock of 24 MHz, the maximum achievable baud rate is 0.75 MBaud.

Standard LIN protocol can support a maximum baud rate of 20 kHz, the baud rate

accuracy is not critical and the fractional divider can be disabled. Only the prescaler is

used for auto baud rate calculation. For LIN fast mode, which supports the baud rate of

20 kHz to 115.2 kHz, the higher baud rates require the use of the fractional divider for

greater accuracy.

Table 30 lists the various commonly used baud rates with their corresponding parameter

settings and deviation errors. The fractional divider is disabled and a module clock of

24 MHz is used.

The fractional divider allows baud rates of higher accuracy (lower deviation error) to be

generated. Table 31 lists the resulting deviation errors from generating a baud rate of

115.2 kHz, using different module clock frequencies. The fractional divider is enabled

(fractional divider mode) and the corresponding parameter settings are shown.

Table 30

Typical Baud rates for UART with Fractional Divider disabled

Baud rate

Prescaling Factor

(2BRPRE)

Reload Value

(BR_VALUE + 1)

Deviation Error

19.2 kBaud

1 (BRPRE=000

78 (4E

H)0.17 %

9600 Baud

1 (BRPRE=000

156 (9C

H)0.17 %

4800 Baud

2 (BRPRE=001

156 (9C

H)0.17 %

2400 Baud

4 (BRPRE=010

156 (9C

H)0.17 %

baud rate

PCLK

BRPRE

BR_VALUE

()

------------------------------------------------------------------------------------ where 2

BRPRE

BR_VALUE

() 1

baud rate

PCLK

BRPRE

BR_VALUE

()

------------------------------------------------------------------------------------

STEP

256

---------------

XC888LM Datasheet(PDF) 94 Page - Infineon Technologies AG

XC888LM Datasheet(HTML) 94 Page - Infineon Technologies AG

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