Acces PCI-ICM422/2, Руководство пользователя

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PCI-ICM422/2(4) and 485/2(4) Manual
Page 5-2
Manual MPCI-ICM4S.F1b
When the BAUD jumper is in the X1 position, the UART clock frequency is 1.8432 Mhz. When the
jumper is in the X4 position, the clock frequency is 7.3728 MHz. The following table lists popular
divisor frequencies. Note that there are two columns to consider depending on the position of the
BAUD jumper.
Bau d Rate Divisor
x1
Divisor
x4
No tes: M ax Diff. Cable Length *
460800 N/A 1
230400 N/A 2
153600 N/A 3
115200 1 4 375 feet
57600 2 8 660 ft
38400 3 12 920 ft
28800 4 16 116 5 ft
19200 6 24 162 0 ft
14400 8 32 205 0 ft
9600 12 48 Most common industrial
speed
400 0 ft
4800 24 96 400 0 ft
2400 48 192 400 0 ft
1200 96 384 400 0 ft
* Recommended maximum distances for differentially driven data cables (RS422 or RS485) are for
typical conditions.
Table 5-1:
Baud Rate Divisor Values
In C, the code to set the chip to 9600 baud is:
outportb(BASEADDR, 0x0C);
outportb(BA1,0);