Motorola MVME2400 manual General-Purpose Software-Readable Header

Preparing the MVME240x Hardware

	J9		J9		J9
1		1		1
2		2		2
3		3		3
Automatic System Controller		System Controller Enabled		System Controller Disabled
(factory configuration)

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.

1

1

1 2 3 4 5 6 7 8

ON

161

SRH0 = 0

SRH1 = 0

SRH2 = 0

SRH3 = 0

SRH4 = 0

SRH5 = 0

SRH6 = 0

SRH7 = 0

1 2 3 4 5 6 7 8

ON

16

SRH0 = 1 SRH1 = 1 SRH2 = 1 SRH3 = 1 SRH4 = 1 SRH5 = 1 SRH6 = 1 SRH7 = 1

Figure 1-2. General-Purpose Software-Readable Header

http://www.mcg.mot.com/literature 1-11