Quatech DS-102 user manual Baud Rate Selection, Factory default

BAUD RATE SELECTION

The 16450 or 16550 UART determines the baud rate of the serial output using a combination of the clock input frequency and the value written to the divisor latches. Standard personal computer serial interfaces use an input clock of 1.8432 MHz. To increase versatility, the DS-102 uses an 18.432 MHz crystal and a frequency divider circuit to produce the standard clock frequency.

Jumper block J1 is used to set the frequency input to the UART. It may be connected to divide the clock input by 1, 2, 5, or 10. A table of baud rates available using the 1.8432 MHz input is given in Figure 25.

For compatibility with standard serial ports, J1 should be configured to divide by 10 as shown in Figure 24(d).

J1

4 5 6 4 5 6

1 2 3 1 2 3

Divide-by-1 input clock	Divide-by-2 input clock
(A)	(B)

4 5 6

1 2 3

Divide-by-5 input clock

(C)

4 5 6

1 2 3

Divide-by-10 input clock

Factory default

(D)

Figure 24 --- Input clock frequency options

Quatech DS-102 User's Manual 25