Software-Readable Header (Srh) Switch (S3); Figure 1-2. Software-Readable Header - Motorola MVME2400 Series Installation And Use Manual

Hardware Preparation and Installation
1

Software-Readable Header (SRH) Switch (S3)

1
1-10
J9
1
2
3
Automatic System Controller
(factory configuration)
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.
16
ON
SRH0 = 0
SRH1 = 0
SRH2 = 0
SRH3 = 0
SRH4 = 0
SRH5 = 0
SRH6 = 0
SRH7 = 0

Figure 1-2. Software-Readable Header

J9
1
2
3
System Controller Enabled
1
ON
Computer Group Literature Center Web Site
J9
1
2
3
System Controller Disabled
16
SRH0 = 1
SRH1 = 1
SRH2 = 1
SRH3 = 1
SRH4 = 1
SRH5 = 1
SRH6 = 1
SRH7 = 1