IBM DS-2000 warranty AUD Rate Selection

B

AUD RATE SELECTION

J1

J1

+-----------

+

+-----------

+

1

o

o+ o

4

1

o--

o

o

4

2

o

o+ o

5

2

o

o--

o

5

+-----------

+

+-----------

+

(a) ÷1

input

clock

(b)

÷2

input

clock

J1

J1

+-----------

+

+-----------

+

1

o

o--

o

4

1

o+ o--

o

4

2

o--

o

o

5

2

o+ o--

o

5

+-----------

+

+-----------

+

(c) ÷5

input

clock

(d)

÷10

input

clock

F i g u r e 1 4 .

I n p u t c l o c k f r e q u e n c y o p t i o n s .

F o r

compatibility,

the

jumper

should be

set at

÷10

(

18.432

MHz

÷

10

= 1.8432 MHz ).

T h e b a u d r a t e m a y n o w b e c a l c u l a t e d u s i n g t h e

equation

crystal frequency

baud rate

= -------------------

16 x divider x DL

where

divider = the clock divider setting of jumper J1 DL = the value programmed into the baud rate

divisor latches of the 16550.

+	-----------	+	-------------	+-----------------------		+
	Desired		Divisor		Error Between Desired
	Baud Rate		Latch Value		and Actual Value (%)
+	-----------	+	-------------	+-----------------------		+
	110		1047		0.026
	300		384		-
	1200		96		-
	2400		48		-
	4800		24		-
	9600		12		-
	19200		6		-
	38400		3		-
	56000		2		2.86
+	-----------	+	-------------	+-----------------------		+

Figure 15 . Divisor latch settings for common baud rates using a 1.8432 MHz input clock.

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