NorthStar HSIO-4 User's & Technical Manual page 63

4.2
DATA BUFFERS
4.3
BAUD RATE GENERATOR
North Star HSIO-4
The Data Buffers interface the S-100 bus Data
Out (DO) and Data In (DI) lines to a single
bidirectional bus on the HSIO-4. During S-100
bus writes, the Data Buffers gate data from
the S-100 DO bus onto the HSIO-4 internal bus.
During USART reads, the buffers gate the read
data onto the S-100 DI bus.
Each of the four ports can be programmed to
select one of eight baud rates. These eight
baud rates are derived from eleven frequencies
produced by the Baud Rate Generator as shown
in Table 4-1:
1760
4800
9600
76800
153600
307200
610
1220
19200
38400
55800
The first six frequencies go directly to the
I/O ports. Of the next four frequencies, only
two go to the I/O ports. The two frequencies
that are allowed to go to the I/O ports for
program selection are selected by mini-jumps
at JP13. The eleventh frequency (55800 Hz) can
be selected by a mini-jump at JP13.
selected, this frequency goes directly to all
four Clock Headers.
58
Table 4-1
Hz or
(110
X
Hz or (300
X
Hz or (600
X
Hz or (4800
X
Hz or (9600
X
Hz or (19200
X
Hz or (75
X
Hz or (150
X
Hz or
(1200
X
Hz or (2400
X
Hz
User/Technical Manual
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