Chapter 2: Hardware Installation
2.5
Echo
User's Manual, ver. 0.00
Interrupt Selection
You can configure Echo boards to use one, two or no interrupt
request lines. To select the appropriate configuration, you must
program DIP switch 8 on SW1 and the IRQ jumper block J1.
When DIP switch 8 is on, all Echo communication ports will
interrupt on the A channel. When switch 8 is off, the odd
numbered Echo ports will interrupt on the A channel, while the
even numbered Echo ports will interrupt on the B channel.
IRQ jumper block J1 allows the assignment of IRQ lines to both
the A and B channels. If your application requires no interrupts
then you can remove both jumpers from jumper block J1. To
assign interrupts to either channel, go to the posts under the
selected IRQ line number and install the jumper(s) between the
centre post and the A post (A channel), and/or between the centre
post and the B post (B channel).
COM1 and COM2 normally use IRQ 4 and IRQ 3 respectively.
If you use the first two ports as COM1 and COM2, set switch 8
on SW1 to the off position and install a jumper between the
centre post and the A post on J1 under IRQ 4 (COM1). You
should install the other jumper between the centre post and the B
post on J1 under IRQ 3 (COM2). If you configure only one of
the two ports as a standard COM1 or COM2, then you can
relocate or remove the other jumper according to the
requirements of the controlling software. Please refer to
Figure 3
for an explanation of IRQ jumper block J1.
Figure 3:
IRQ jumper block J1
3
4
5
7 10 11 12 15
B
A
Note:
this example of shows J1 selected for IRQ 3 and 4 on
channels B and A respectively.
