Rainbow-electronics ATtiny2313 Bedienungsanleitung PDF herunterladen (Seite 136)

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ATtiny2313

2543A–AVR–08/03

Examples of Baud Rate

Setting

For standard crystal and resonator frequencies, the most commonly used baud rates for

asynchronous operation can be generated by using the UBRR settings in Table 57.

UBRR values which yield an actual baud rate differing less than 0.5% from the target

baud rate, are bold in the table. Higher error ratings are acceptable, but the Receiver will

have less noise resistance when the error ratings are high, especially for large serial

frames (see “Asynchronous Operational Range” on page 128). The error values are cal-

culated using the following equation:

Error[%]

BaudRate

Closest Match

BaudRate

-------------------------------------------------------- 1– 100%•=

Table 57. Examples of UBRR Settings for Commonly Used Oscillator Frequencies

Baud

Rate

(bps)

osc

= 1.0000 MHz f

osc

= 1.8432 MHz f

osc

= 2.0000 MHz

U2X = 0 U2X = 1 U2X = 0 U2X = 1 U2X = 0 U2X = 1

UBRR Error UBRR Error UBRR Error UBRR Error UBRR Error UBRR Error

2400 25 0.2% 51 0.2% 47 0.0% 95 0.0% 51 0.2% 103 0.2%

4800 12 0.2% 25 0.2% 23 0.0% 47 0.0% 25 0.2% 51 0.2%

9600 6 -7.0% 12 0.2% 11 0.0% 23 0.0% 12 0.2% 25 0.2%

14.4k 3 8.5% 8 -3.5% 7 0.0% 15 0.0% 8 -3.5% 16 2.1%

19.2k 2 8.5% 6 -7.0% 5 0.0% 11 0.0% 6 -7.0% 12 0.2%

28.8k 1 8.5% 3 8.5% 3 0.0% 7 0.0% 3 8.5% 8 -3.5%

38.4k 1 -18.6% 2 8.5% 2 0.0% 5 0.0% 2 8.5% 6 -7.0%

57.6k 0 8.5% 1 8.5% 1 0.0% 3 0.0% 1 8.5% 3 8.5%

76.8k – – 1 -18.6% 1 -25.0% 2 0.0% 1 -18.6% 2 8.5%

115.2k – – 0 8.5% 0 0.0% 1 0.0% 0 8.5% 1 8.5%

230.4k––––––00.0%––––

250k––––––––––00.0%

Max.

(1)

62.5 kbps 125 kbps 115.2 kbps 230.4 kbps 125 kpbs 250 kbps

1. UBRR = 0, Error = 0.0%

1 2 ... 131 132 133 134 135 136 137 138 139 140 141 ... 210 211

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