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BAUD RA
9 ,600.
4,800.
2,400.
1
,800.
1
,200.
600.
300.
200.
150.
134.
110.
75.
50.
In some applications, values are being accumulated and recognition of a
particular count event is desired.
This might be accomplished by
pre10ading the counter with the desired value and then counting it down
toward zero.
Alternatively, the counter can be initialized with zero
and the desired value entered into the Alarm register.
With the
Comparator enabled, an OUT transition will then occur when the value is
reached, plus counts will continue to accumulate.
OUTPUT CONTROL BIT
The output control circuitry for each of the five counter groups
includes a toggle flip-flop that can be used to generate various output
waveforms.
TC from the counter is the toggling signal and the output
frequency can thus be half the TC frequency.
The toggl e can be
initialized to either high or low state by command.
More details of
the
toggle
activity
are
included
in
the
Counter Mode
Register
description.
BAUD RATE PROGRAMMING
The Am96/4116A uses the Am9513 System Timing Controller as the on-board
clock source for the two serial ports.
As shipped, both ports are set
to function at 9600 baud.
(FOUT from the Am9513).
The Am9551 clock
sources may jumpered to Am9513 OUT3 (U6) and OUT4 (U22).
OUT3 and OUT4
are the outputs of counters 3 and 4 respectively.
The jumpers should
be located between pi ns 138 and 139 (U22) and pi ns 142 and 143 (U6).
Tab1e 3-5 1is ts the Load Reg i ster va 1ues to be prog rammed fo r the
desired baud rate.
The table assumes a frequency source of Fl and FOUT
. divide-by-one, which are selected by the programmer, and a synchronous
communications.
The counter output frequencies are 16X the baud rate.
The maximum baud rate is 9600 for asynchronous
and 38,400 for
synchronous mode.
TABLE 3-5.
BAUD RATE SELECTION
TE
DECIMAL
HEX
0
16
0010
0
32
0020
0
64
0040
0
85
0055
0
128
0080
0
256
0100
0
512
0200
0
768
0300
0
1024
0400
5
1142
0476
0
1396
0574
0
2048
0800
0
3072
OCOO
3-32
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