PAGE
5
PC B
OARD
- PC-188 B
ITBUS
I/F
FOR
IBM-PC
O
RDER
NO
. 5904512211
M
AY
2002 - R
EV
. 1.2
4. Board configuration
4.1 Type of transmission
The transmission rate is strictly related to the perfor-
mance to be achieved by the network. Up to 13.2Km
can be reached with 62.5KB. On the other hand, the
distance is reduced to 900 m when the 375Kbps rate is
used.
The transmission rate is set by inserting jumper JA0 for
62.5KB and removing it when 375KB is used.
4.2 Node address
The node address simply identifies the node inside the
Bitbus network. Addresses can be configured within a
range of 01H-FAH for slave nodes while address 00H is
for the network master and addresses FBH-FFH are
reserved, as per directives IEEE 1118.
The node address is set with jumpers JS0-JS7. Jumper
JS0 corresponds to the least significant bit, while jumper
JS7 is for the most significant one. A short-circuited
jumper corresponds to 1 in the binary configuration of
the address. When open, it corresponds to 0. The relation
between the jumper/bit of an address is shown in the
figure below:
Figure 4.2.1 Node address configuration.
RAM
SLOT *0
XP1
RAM1MJ3
RAM4MJ2
EPROM/FLASH
XP2
RL
GL
SER
+5V
XS1
J3
J2
J6
J4
J16
JF0
JF1
2
3
4
5
6
JF
JF
JF
JF
JF
JA0
JA1
2
3
4
5
6
JA7
JA
JA
JA
JA
JA
JS0
JS1
2
3
4
5
6
JS7
JS
JS
JS
JS
JS
J12
J13
J11
J9
J10
J8
J7
JQ9
JQ7
JQ6
JQ5
JQ4
JQ3
JQ10
JQ1
1
JQ12
JQ15
JQ14
JT1
JT2
NORMAL
SLOT*0
1
1
1
J14
J17
Tint
Rint
TERM
1
JS0
JS1
JS2
JS3
JS4
JS5
JS6
JS7
JMP
bit0
bit1
bit2
bit3
bit4
bit5
bit6
bit7
Bits
LSB
MSB
JQ14
1
J
4.3 External storage
configuration
The CPU can be provided with up to 512KB EPROM/
CODE FLASH and up to 512KB DATA RAM. The default
configuration is 128K CODE EPROM and 62K DATA RAM.
Figure 4.3.1
The dimensions of the DATA RAM are set by using
jumpers J2 and J3:
Table 4.3.1
The dimensions of the EPROM/CODE FLASH is set by
using jumpers J16, J4 and J6.
Tabella 4.3.2
4.4 Interface with the PC
The base address where the PC-188 board is located
should be selected by the user with jumpers JF0-JF6. It
can range from 000H to 3F8H with 8 byte blocks. The
address jumper relation is shown in the table below:
Table 4.4.1 Relation between bit/jumper for selecting the board
base address.
Bit2, bit1 and bit0 are used to decode the particular
addressed byte (data, command, state).
When the jumpers are put in, “1” is typed in for the
respective bit which will then be compared to the bus
address. Bit9 of the address has to be 1. Table 4.4.1
illustrates the default configuration of these jumpers.
CODE
MEMORY
(EPROM
or
FLASH)
DATA
MEMORY
(RAM)
80000H
00000H
FFFFFH
7FFFFH
J3 ON
J3 OFF
J2 OFF
J2 ON
RAM 32/128×8
RAM 512×8
J16 1-2
J16 2-3
EPROM 1/4 MB
FLASH 1/4 MB
J6 ON
J6 OFF
J4 OFF
J4 ON
FLASH 1/4 MB
EPROM 1/4 MB
JF6
bit9
ins.
bits
Jumper
default
(208H)
JF2
bit5
NO
JF4
bit7
NO
JF0
bit3
ins.
JF5
bit8
NO
JF1
bit4
NO
JF3
bit6
NO
