System Controller Functions - PEP VM162 User Manual

VM162/VM172
2.5.1.2 VME Address Map
The various combinations of addressing modes and data bus sizes are selected on different address areas
within the address map of the CPU. The corresponding AM codes are generated according to the Table
below.
Table 2.6: Generated AM Codes
VME VME
AM Code Cycle Type
0E/0D/0A/09 A32/D32
0E/0D/0A/09 A32/D16
3E/3D/3A/39 A24/D32
3E/3D/3A/39 A24/D16
2D/29 A16/D32
2D/29 A16/D16
Note: The A32 VME addressing modes begin at VME offset 0, independent of their location within the
CPU address map.
Supervisor/use or program/data AM codes are generated, dependent on the type of CPU access that is
running.

2.5.2 System Controller Functions

2.5.2.1 Automatic First-Slot Detection
During power-up, the VM162/VM172 automatically detects if the board is placed in the far left slot of
the system. If so, it acts automatically as the system controller.
Note: This information is stored in the FSD (First Slot Detection) bit within the VMEbus Control/Status
register.
2.5.2.2 SYSCLK* Generator
The VMEbus SYSCLK* driver of the VM162/VM172 is controlled directly by the FSD bit. That means,
if the board has detected itself as system controller it will automatically drive SYSCLK* to the VME-
bus. If it has detected not to be system controller its SYSCLK* driver is automatically disabled.
Note: The system integrator has to ensure that there is only one SYSCLK driver active for the whole sy-
stem. This is especially important where boards with jumper enabled SYSCLK drivers are mixed with
VM162/VM172 boards.
Page 2- 10
Chapter 2 Functional Description
Size VME Address Range
(HEX) (HEX)
512 MByte 00 00 00 00 - 1F FF FF FF
256 MByte 00 00 00 00 - 0F FF FF FF
16 MByte xx 00 00 00 - xx FF FF FF
16 MByte xx 00 00 00 - xx FF FF FF
64 kByte xx xx 00 00 - xx xx FF FF
64 kByte xx xx 00 00 - xx xx FF FF
© PEP Modular Computers
CPU Address Range
(HEX)
A0 00 00 00 - BF FF FF FF
90 00 00 00 - 9F FF FF FF
8F 00 00 00 - 8F FF FF FF
87 00 00 00 - 87 FF FF FF
8D 00 00 00 - 8D 00 FF FF
85 00 00 00 - 85 00 FF FF
Juli 23, 1997