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2.8
BAUD RATE JUMPER
Upon SUPER SIX initialization, the baud rate for the two serial channels can be
hardware-selected independently by means of the baud rate jumper (J7).
This 7-pole
jumper is located between
U70
and U68 and is divided into two sets of jumpers containing
four and three pins for SIO channels A and B, respectively. Pins 7, 6, 5, and 4 set the baud
rate for SIO channel A and are designated as A, B, C, and D, respectively; pins 3, 2, and I
set the baud rate for SIO channel B and are designated as A, B, and C, respectively.
Because this jumper comprises of only seven pin sets, SIO channel B has a hardware
limitation of
1200
baud; by means of port 18 the software may be set to allow up to 19.2K
baud for channel B. The baud rate settings, as determined by this jumper, are shown in
Table 2-1, below. Once the SUPER SIX is initialized, I/O port 18 is used to modify the
baud rate. Port 18 is described in subsection 3.2.2 L
BIT
BIT
BIT
BIT
BAUD
D
C
B
A
RATE
0
0
0
0
50
0
0
0
I
75
0
0
I
0
110
0
0
I
I
134.5
0
I
0
0
150
0
I
0
I
300
0
I
I
0
600
0
I
I
I
1200
I
0
0
0
1800
I
0
0
I
2000
I
0
I
0
2400
I
0
I
I
3600
I
I
0
0
4800
I
I
0
I
7200
I
I
I
0
9600
I
I
I
I
19,200
Table 2-1. SUPER SIX Baud Rate Jumper Settings
2.9
EPROM AND MONITOR OPERATION
The on-board EPROM occupies addresses FOOO-FFFF (hex). This EPROM is switched ON
automatically during RESET or POWER-ON. It contains the serial input/output (SIO) and
floppy disk controller (FDC) initialization code along with a simple debugger and floppy
disk cold-start loader. After the operating system is loaded the EPROM can be turned
OFF to allow access to the RAM at address FOOOH-FFFFH. The EPROM can be enabled
or disabled at any time to permit the calling of hardware dependant I/O routines.
2.9.1
EPROM Enable/Disable
A listing of-the program required to enable and disable the EPROM is provided below
-7-
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