8
The ISA Bus interrupt request lines IRQ3, IRQ4, IRQ5, IRQ6, IRQ7, IRQ9, IRQ10, and IRQ11 are
connected to I0 to I7 of the MC68HC901. The requested interrupt is then routed to -IRQ1 of the
MCF5204.
3.7 THE CONNECTORS AND THE EXPANSION BUS
There are ten connectors on the SBC5204 which are used to connect the board to external I/O devices and
or expansion boards. This section provides a brief discussion and the pin assignments of the connectors.
3.7.1 The Terminal Connector J1
The SBC5204 uses a 9-pin D-sub female connector J1 for connecting the board to a terminal or a PC with
terminal emulation software. The available signals are a working subset of the RS-232C standard. Table
3.2 shows the pin assignment.
TABLE 3.2. The J1 (TERMINAL) Connector pin assignment.
PIN NO.
DIRECTION
SIGNAL NAME
1
Output
Data Carrier Detect (shorted to 4 & 6)
2
Output
Receive data
3
Input
Transmit data
4
Input
Data Terminal Ready (shorted to 1 & 6)
5
Signal Ground
6
Output
Data Set Ready (shorted to 1 & 4)
7
Input
Request to Send (shorted to 8)
8
Output
Clear to Send (shorted to 7)
9
Not Used
3.7.2 The ISA Bus Auxiliary Power Connector J2
The ISA Bus re/-12 and -5 as well as +5 volts supply. Since they are not always needed the
connector used for these is a simple burg connector. Table 3.3 shows the Pin assignment for J2.
TABLE 3.3. The J2 Connector pin assignment.
PIN NUMBER
SIGNAL NAME
1
+12 Volts
2
Ground
3
-12 Volts
4
-5 Volts
