Ibm uPD78082 Manual do Utilizador descarregar pdf (Página 178)

155

CHAPTER 11 SERIAL INTERFACE CHANNEL 2

The baud rate transmit/receive clock generated is either a signal scaled from the main system clock, or

a signal scaled from the clock input from the ASCK pin.

(i) Generation of baud rate transmit/receive clock by means of main system clock

The transmit/receive clock is generated by scaling the main system clock. The baud rate generated

from the main system clock is obtained with the following expression.

[Baud rate] = [Hz]

where, f

X : Main system clock oscillation frequency

XX : Main system clock frequency (fx or fx/2)

n : Value set in TPS0 to TPS3 (1 ≤ n ≤ 11)

k : Value set in MDL0 to MDL3 (0 ≤ k ≤ 14)

Table 11-5. Relation between Main System Clock and Baud Rate

fx=5.0 MHz fx=4.19 MHz

MCS=1 MCS=0 MCS=1 MCS=0

BRGC Set Value Error (%) BRGC Set Value Error (%) BRGC Set Value Error (%) BRGC Set Value Error (%)

75 – 00H 1.73 0BH 1.14 EBH 1.14

110 06H 0.88 E6H 0.88 03H –2.01 E3H –2.01

150 00H 1.73 E0H 1.73 EBH 1.14 DBH 1.14

300 E0H 1.73 D0H 1.73 DBH 1.14 CBH 1.14

600 D0H 1.73 C0H 1.73 CBH 1.14 BBH 1.14

1200 C0H 1.73 B0H 1.73 BBH 1.14 ABH 1.14

2400 B0H 1.73 A0H 1.73 ABH 1.14 9BH 1.14

4800 A0H 1.73 90H 1.73 9BH 1.14 8BH 1.14

9600 90H 1.73 80H 1.73 8BH 1.14 7BH 1.14

19200 80H 1.73 70H 1.73 7BH 1.14 6BH 1.14

31250 74H 0 64H 0 71H –1.31 61H –1.31

38400 70H 1.73 60H 1.73 6BH 1.14 5BH 1.14

76800 60H 1.73 50H 1.73 5BH 1.14 — —

Remark MCS: Oscillation mode selection register (OSMS) bit 0

fXX

× (k+16)

Baud

Rate

(bps)

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