5. Each Component Function
60 User’s Manual
Table 5.10. Function of Each Register < 4 / 4 >
MSR : Modem Status Register
D7 D6 D5 D4 D3 D2 D1 D0
03FEH
I/O address Description
SCR : Scratchpad Register
03FFH
DCD RI DSR CTS DDCD
TERI
DDSR
DCTS
Delta CTS
Delta DSR
Trailing edge RI
Delta data carrier detect
CTS
DSR
RI
DCD
This is an 8-bit, readable/writable register which is available to the user to
allow data to be saved temporarily.
Since these
statuses are
not used with
RS-485, data
is not valid.
Setting Baud Rates
A baud rate is set by software by dividing the clock input
(1.8432MHz). To set a baud rate, write a value found in the
following list to the divisor latch registers (LSB and MSB).
Table 5.11. Baud Rate Settings
Setting error (%)
50 2304 ---
75 1536 ---
110 1047 0.026
857 0.058
150 768 ---
300 384 ---
600 192 ---
1200 96 ---
1800 64 ---
2000 58 0.69
2400 48 ---
3600 32 ---
4800 24 ---
7200 16 ---
9600 12 ---
19200 6 ---
Example: To set 9,600 bps, write "00" to the (MSB) divisor latch
register and "12 (decimal)" to the (LSB) divisor latch register.
Baud rate to be set
Value to be set
in the divisor register
134.5
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