Motorola MVME2400 - Manual (Page 27)

Preparing the MVME240x Hardware
http://www.mcg.mot.com/literature 1-11
1
Setting the General-Purpose Software-Readable Header (SRH) Switch(S3)
Switch S3 is an eight pole single-throw switch with software readable
switch settings. These settings can be read as a register at ISA I/O address
$801 (hexadecimal). Each switch pole can be set to either logic 0 or logic
1. A logic 0 means the switch is in the “ON” position for that particular bit.
A logic 1 means the switch is in the “OFF” position for that particular bit.
SRH Register Bit 0 is associated with Pin 1 and Pin 16 of the SRH, and
SRH Register Bit 7 is associated with Pin 8 and Pin 9 of the SRH. The SRH
is a read-only register.
If Motorola’s PowerPC firmware, PPCBug, is being used, it reserves all
bits, SRH0 to SRH7. If it is not being used, the switch can be used for other
applications.
Figure 1-2. General-Purpose Software-Readable Header
1
2
3
J9
System Controller Disabled
1
2
3
J9
Automatic System Controller
(factory configuration)
1
2
3
J9
System Controller Enabled
SRH0 = 0
SRH1 = 0
SRH2 = 0
SRH3 = 0
SRH4 = 0
SRH5 = 0
SRH6 = 0
SRH7 = 0
SRH0 = 1
SRH1 = 1
SRH2 = 1
SRH3 = 1
SRH4 = 1
SRH5 = 1
SRH6 = 1
SRH7 = 1
ON ON
1 1 16 16
12345
678
1234
5678