Motorola 700/800-Series 用户手册

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页码 153
2-12
Hardware Preparation and Installation
2
General-Purpose Readable Jumpers Header (J21)
Header J21 provides eight readable jumpers. These jumpers are 
read as a register (at $FFF4202D) in the MC2chip LCSR (local 
control/status register). The bit values are read as a 0 when the 
jumper is installed, and as a 1 when the jumper is removed.
With the factory-installed MVME162BUG firmware in place, four 
jumpers are user-definable (pins 9-10, 11-12, 13-14, 15-16). If the 
MVME162BUG firmware is removed, seven jumpers are user-
definable (i.e., pins 1-2, 3-4, 5-6, 9-10, 11-12, 13-14, 15-16).
Note
Pins 7-8 (GPI3) are reserved to select either the Flash 
memory map (jumper installed) or the EPROM 
memory map (jumper removed). They are not user-
definable. The address ranges for the various 
EPROM/Flash configurations appear in the section on 
header J20.
In most cases, the MVME162LX is shipped from the factory with J21 
set to all zeros (jumpers on all pins) except for GPI3 (pins 7-8). On 
boards built with the no-VMEbus option
, however, GPI3 is jumpered 
as well.
Table 2-6.  EPROM/Flash Mapping — 1M x 8 EPROMs, Onboard Flash 
Disabled
GPI3
Address Range
Device Accessed
Removed 1 $FF800000 - $FF8FFFFF EPROM A (XU1)
$FF900000 - $FF9FFFFF EPROM B (XU2)
Not used
Onboard Flash
Installed
0 Not used
Onboard Flash
$FF800000 - $FF8FFFFF EPROM A (XU1)
$FF900000 - $FF9FFFFF EPROM B (XU2)