SYSTEM Electronics PC-188 User manual

Table of contents
1. Bitbus specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
2. Main board features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
3. Inspection and installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
4. Board configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
4.1 Type of transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2 Node address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.3 External storage configuration . . . . . . . . . . . . . . . . . . . . . . . 5
4.4 Interface with the PC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.5 Message transfer mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.6 Terminal resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.7 Additional functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.7.1 Expansion slot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.8 Default configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.9 Bitbus network connectors . . . . . . . . . . . . . . . . . . . . . . . . . . 7

PAGE 2
PC BOARD - PC-188 BITBUS I/F FOR IBM-PC
ORDER NO. 5904512211MAY 2002 - REV. 1.1
SYSTEM SPA (Electronics Div.) reserves the right to
make changes to the specifications at any time without
giving prior notice. The information contained herein is
correct and reliable. No part of this publication may be
reproduced in any form without prior authorisation from
SYSTEM SPA (Electronics Div.).
DICO is a registered trademark of SYSTEM SPA
(Electronics Div.).
BITBUS is a registered trademark of Intel Corporation.
IBM is a registered trademark of International Business
Machines Corporation.
Any other product names mentioned in this publication
are the property of their respective manufacturers.
This product meets the EMC requirements
of EEC directive 89/336.
Revisions Pages
Rev. 1.0 Compilation 7
Rev. 1.1 Alteration 7
Rev. 1.2 Alteration Table 4.4.1 7
SYSTEM s.p.a. Div. Electronics
via Ghiarola Vecchia, 73
41042 Fiorano (Mo) Italy
tel [phone] - fax [phone]
www.system-group.it
e-mail: [e-mail]

PAGE 3
PC BOARD - PC-188 BITBUS I/F FOR IBM-PC
ORDER NO. 5904512211MAY 2002 - REV. 1.2
1. Bitbus specifications
The Bitbus is a serial communication system based on
electrical code RS485 that employs an SDLC protocol.
The network is based on a hierarchy that has a single
master node that communicates with several slave
nodes. Each slave can work as a master for another
Bitbus network, thereby constituting a multiple hierarchy.
This is particularly useful in applications that require
different transmission rates (Figure 1.1).
Figure 1.1 Typical Bitbus network connection.
The Bitbus interconnection may work in two different
ways: synchronous mode and self-clocked mode. The
first uses a faster transmission rate but is limited as far
as distance and number of network nodes are concerned.
Due to these drawbacks, the PC-188 board uses only
the self-clocked mode.
SELF-CLOCKED MODE: unlike the previous mode, this
is suitable for long-distance transmission. Two different
transmission rates are employed: 375Kbit/sec and
62.5Kbit/sec. The first transmission rate is able to cover
distances of up to 300m with a max of 28 nodes connected
to the line.
On the other hand, the 62.5Kbit/sec rate covers a max
distance of 1200m with the same number of nodes. For
longer distances, the repeaters have to be used and a
max of 250 nodes can be connected. Figure 1.2 illustrates
the self-clocked mode connection with repeaters.
Figura 1.2 Example of Bitbus network connection in self-
clocked mode with repeaters.
MASTER
MASTERMASTER
SLAVE
SLAVE
SLAVE
SLAVE
Bitbus
Bitbus Bitbus
SLAVE
DATA PAIR
DATA PAIR
RTS PAIR
MASTER
SLAVE
SLAVE
REPEATER
REPEATER
REPEATER
Transmission in synchronous mode (not supported) and
self-clocked mode with repeaters is implemented with
screened five-wire cables (a twisted pair for DATA, DATA-
another pair of twisted cables is used for RTS, RTS- and
a RGND reference wire), Figure 1.3.
Figure 1.3 Connections for synchronous or self-clocked mode
with repeaters.
A shielded 3-wire cable is required when using self-
clocked mode without repeaters (a twisted pair dedicated
to DATA and DATA- transmission and a RGND reference
wire), Figure 1.4.
Figura 1.4 Connection for self-clocked without repeaters.
The correct layout of the various modes is shown in
Figure 1.5. In particular, there cannot be any star
networks and, moreover, terminal resistors have to be
placed at either end of the network. The rating of the
terminal resistors has to match the typical impedance
of the connecting cable to prevent reflectance on the
line.
Figure 1.5 Correct layout of Bitbus network nodes.
Table 1.1 Bitbus network operating modes.
DATA
DATA*
DCLK/RTS
DCLK/RTS*
RGND
DATA
DATA*
RGND
R term.
R term.
SELF/CLOCKED
62.5 Kbps
SELF/CLOCKED
375 Kbps
nodes between repeaters
max repeaters on Bitbus line
max nodes on Bitbus line
max distance between repeaters
total distance used by Bitbus line
pairs of lines required
10
251
1200m
13.2Km
1 (no repeaters)
2 (with repeaters)
28
2
84
300m
900m

PAGE 4
PC BOARD - PC-188 BITBUS I/F FOR IBM-PC
ORDER NO. 5904512211MAY 2002 - REV. 1.1
2. Main board features
The PC-188 is an expansion board for IBM/AT or IBM/
XT PCs and compatibles. The board is used to interface
the PC with the Bitbus network.
Typical Bitbus applications include industrial automation,
process control, data acquisition, etc….
•CPU Am188ES
•CPU clock frequency: 40MHz
•Configurable external data storage capable of
supporting RAM ranging from 32Kx8 to 512Kx8.
The data memory address ranges from 00000H up
to 7FFFFH
•Configurable external code storage capable of
supporting various EPROMs and FLASH EPROM
ranging from 128Kx8 to 512Kx8. The addresses go
from 80000H to FFFFFH
•External I/O space mapped I/O, starting from 00H
•Bitbus serial interface that supports the self-
clocked mode (baud rate 375Kbit/sec or 62.5Kbit/sec)
•The Bitbus network is opto-insulated through the
internal logic system (500VDC)
•The board is protected against transient
interferences affecting the Bitbus network
•Connection to the Bitbus network with two DB-9
connectors (1 male and 1 female, parallel-
connected)
•PC-parallel interface consisting of two
unidirectional 9 bit, 1 byte FIFOs, two registers for
extra-Bitbus communications and a few Status bits
•One CPU Am188ES interface (RS232)
•One expansion slot for an additional serial
interface such as RS232, RS485, RS422, CAN or
second Bitbus network
•Required operating conditions:
Temperature: 0-60 °C
Relative humidity: UR 85%, no condensate
•Dimensions:
Length: 17.5 cm
Width: 10.7 cm
Weight: 180 grams
•Power requirements: 2.5W (5VDC ±5%)
3. Inspection and
installation
After receiving the PC-188 board, make sure it has not
been damaged in any way during shipment. If damage
is found, contact SYSTEM Electronics.
The board is supplied in the following default configuration:
Table 3.1 Board default configuration.
Before installing the PC-188 board, establish the per-
formance to be achieved and configure the board as
required. Proceed as directed below:
1) If the board is NOT at the ends of the network,
detach jumpers JT1 and JT2 for the terminal
resistors of the RTS and DATA lines.
2) While wiring up the Bitbus line, make sure the
cables for the DATA and RTS lines are of the same
type and length in order not to cause any delay.
3) Set the node address and transmission rate with
the jumpers provided.
4) Select the mode in which messages are exchanged
with the PC (polling or interrupt), if necessary.
5) Select the board base address in the I/O space of
the PC.
Refer to the next chapter for more detailed information.
SYNCHRONOUS
FUNCTION
Serial I/F Bitbus
External storage
I/F with PC
Self-clocked mode
Node address: FAH
Terminal resistors activated
Code space configured with 128K EPROM
Data space configured with 32K RAM
I/O addresses
DATA ITEM = 208H
COMMAND = 20AH
STATE
Interrupt jumper not installed
:
= 20CH

PAGE 5
PC BOARD - PC-188 BITBUS I/F FOR IBM-PC
ORDER NO. 5904512211MAY 2002 - REV. 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
JQ11
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

PAGE 6
PC BOARD - PC-188 BITBUS I/F FOR IBM-PC
ORDER NO. 5904512211MAY 2002 - REV. 1.1
The interface with the PC uses a transmission protocol
based on:
-a data byte
-a command byte
-a state byte
-a pair of bytes reserved for future communications
related to application programs and not directly
connected to the Bitbus communications.
The table below shows the relation between the I/O
port and address according to the selected base address.
Table 4.4.2Relationbetween theI/Oport and addressaccording
to the base address.
4.5 Message transfer mode
Messages can be transferred between the PC and PC-188
board in either polling or interrupt mode. To select the
mode in which data is exchanged, set jumpers JQ3, …,
JQ15. If no jumpers are installed, data is exchanged in
polling mode, vice-versa if the above-mentioned jumpers
are set, interrupt mode will be used.
The interrupt levels available range from level 3 to level
15. Level 10 and 15 are available only if the board is
plugged in on a AT bus. The figure below shows a selection
guide of the interrupt levels for data transmission and
reception.
NOTE:
The PC should have no interrupt sources with the
same interrupt level. Two free interrupt levels, one
for transmission and one for reception, are required
to operate in interrupt mode.
Figure 4.5.1
ADDRESS DEFAULT
ADDRESS
REGISTER
DATO
COMANDO
STATO
Aux da 188
Aux a 188
BASE
BASE + 2
BASE + 4
BASE + 5
BASE + 6
208H
20AH
20CH
20DH
20EH
READ/WRITE
READ/WRITE
READ
READ
WRITE
OPERATIONS
ALLOW
JQ9
JQ7
JQ6
JQ5
JQ4
JQ3
JQ10
JQ11
JQ12
JQ15
JQ14
1
Tint
Rint
4.6 Terminal resistor
If the PC-188 board is installed at the ends of the Bitbus
network, the terminal resistors have to be placed on
the DATA and RTS lines by inserting jumpers JT1 and
JT2. If the board is not at the ends of the Bitbus network,
the two jumpers have to stay open.
4.7 Additional functions
Jumpers JA6 can be used if total compatibility with the
PC-44 version of the board (with 8044 Intel inside) is
required.
If the PC extension executes a RXMEM master node at
addresses FFFE and FFFF when JA6 is set to OFF, the
node and configuration will be obtained as happened
with the old PC-44.
On the other hand, if JA6 is set ON, the contents of the
two storage locations will be provided.
Jumper JA7 can be used to activate (JA7 ON) the dynamic
configuration of the board via FIFO. If JA7 is set to OFF
the board is configured according to the jumper settings.
4.7.1 Expansion slot
The board has a Slot#0 expansion slot than can host
serial interface modules such as RS232, RS422/485 and
CANBUS.
To use the expansion slot, move jumpers J7, …, J12 to
locations 2-3 so that DB9 connector (male XP1) can be
plugged in.
As a result, only DB9 connector (female XS1) is available
for the Bitbus.

PAGE 7
PC BOARD - PC-188 BITBUS I/F FOR IBM-PC
ORDER NO. 5904512211MAY 2002 - REV. 1.2
4.8 Default configuration
Table 4.8.1
Jumper State Function
JS0
JS1
JS2
JS3
JS4
JS5
JS6
JS7
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
00H
00H
00H
00H
00H
00H
00H
00H
set bit 0 of node address
set bit 1 of node address
set bit 2 of node address
set bit 3 of node address
set bit 4 of node address
set bit 5 of node address
set bit 6 of node address
set bit 7 of node address
JF0
JF1
JF2
JF3
JF4
JF5
JF6
ON
OFF
OFF
OFF
OFF
OFF
ON
208H
208H
208H
208H
208H
208H
208H
set bit 3 of PC base address
set bit 4 of PC base address
set bit 5 of PC base address
set bit 6 of PC base address
set bit 7 of PC base address
set bit 8 of PC base address
set bit 9 of PC base address
JA0
JA1
JA2
JA3
JA4
JA5
JA6
JA7
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
Select a speed af 375 Kbps
not used
not used
not used
not used
not used
Fully compatible with 8044 Intel
Dynamic configuration disabled
JQ3
JQ4
JQ5
JQ6
JQ7
JQ9
JQ10
JQ11
JQ12
JQ14
JQ15
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
1-2 connect IRQ3 when transmission is interrupted (PC-188)
2-3 connect IRQ3 when reception is interrupted (PC)
Connect IRQ4 to TINT (1-2) or RTINT (2-3)
Connect IRQ5 to TINT (1-2) or RTINT (2-3)
Connect IRQ6 to TINT (1-2) or RTINT (2-3)
Connect IRQ7 to TINT (1-2) or RTINT (2-3)
Connect IRQ9 to TINT (1-2) or RTINT (2-3)
Connect IRQ10 to TINT (1-2) or RTINT (2-3)
Connect IRQ11 to TINT (1-2) or RTINT (2-3)
Connect IRQ12 to TINT (1-2) or RTINT (2-3)
Connect IRQ14 to TINT (1-2) or RTINT (2-3)
Connect IRQ15 to TINT (1-2) or RTINT (2-3)
J3
J2
J6
J4
J16
J17
J7
J8
J9
J10
J11
J12
J13
ON
OFF
OFF
ON
1-2
OFF
1-2
1-2
1-2
1-2
1-2
1-2
1-2
Select RAM up to 128K×8
Select RAM up to 128K×8
Select EPROM
Select EPROM
Select EPROM
Enable Slot#0 operation
JT1
JT2
ON
ON
Terminals connected to DATA line
Terminals connected to RTS line
Join connector XP1 in parallel
to connector XS1.
If jumpers are moved to position 2-3
XP1 will be connected to Slot#1
4.9 Bitbus network connectors
Two DB-9 connectors (at the input and output of the
line) are provided to connect the board to the Bitbus
network (the pinout is identified as shown in Table 4.9.1).
Table 4.9.1 Pinout of the Bitbus network connectors.
The Bitbus network cable should have the DATA/DATA-
signal pairs and RTS/RTS- twisted and shielded together
with the RGND line as shown in Figures 1.3 and 1.4.
By moving jumpers J7…J12 from location 1-2 (normal)
to position 2-3 (slot#0), the 9-pin male connector XP1
is disconnected from the Bitbus network and joined to
the piggy-back module (optional) placed in slot#0. As a
result, an additional serial interface (RS232, RS422,
RS485 or CAN) is available. By using rectangular
connector XP2, and RS232 interface is always available.
The latter may be used by sending the SYSTEM Electronics
commands defined (Open, Send, Receive, Close) to task
GBS (ex RAC). As an alternative, the library functions of
an application program can be used for the same
purpose. This serial port may also be used for debugging
(at source level) application programs (with tools
provided by SYSTEM Electronics or other manufacturers).
Figure 4.9.1 Jumper location.
SIGNAL SIGNAL
PIN PIN
1
2
3
4
5
6
7
8
9
--
GND
DATA-
RTS-
RGND
--
GND
DATA
RTS
RAM
SLOT *0
EXPANSION SLOT
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
JQ11
JQ12
JQ15
JQ14
JT1
JT2 NORMAL
SLOT*0
1
1
1
J14
J17
Tint
Rint
TERM
1