i4000 - Quad |
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User Manual | Version: 1.2 |
4.VMEBUS INTERFACE
4.1.ADDRESS INTERFACE
The i4000 can be selected to accept either short addressing, using
When using short addressing up to 32 i4000 boards can be put in a single VMEbus system since the lower 11 address lines
The memory space occupied by the i4000 is 0x800 bytes long. This memory space is equally spread across the four modules. So each module occupies 0x200 bytes. From these 0x200 bytes address space half is used by the interrupt controller. The address space for each module is therefore 0x100 bytes long (8 bit addressing).
The address space of the i4000 is selectable using dip switches (SW1 and SW2) which are accessible even when the four module slots are occupied. When a switch is “on” the corresponding address line is a logical “zero” and when a switch is “off” the corresponding address line is “one”.
Address modifier AM4 can be used to select either standard or short memory addressing. If AM4 is “one” (the switch is in the off position) standard addressing is selected. If AM4 is “zero” (switch on) short addressing is selected. When using short addressing the address lines
E X A M P L E :
O f f | O n |
1
2
3
4
5
6
7
8
1
2
3
4
6
7
O f f | A 2 3 |
O n | A 2 2 |
O n | A 2 1 |
O f f | A 2 0 |
O n | A 1 9 |
O n | A 1 8 |
O n | A 1 7 |
O n | A 1 6 |
O n | A 1 5 |
O n | A 1 4 |
O n | A 1 3 |
O n | A 1 2 |
O f f | A 1 1 |
O f f | A M 4 |
Base Adress | SW2 |
0x900800 | SW3 |
( s t a n d a r d a d d r e s s s p a c e )
Figure 4 Address Selection
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