4. Addressing > VGA Addressing
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PEB383 User Manual
July 25, 2011
Integrated Device Technology, Inc.
Confidential - NDA Required
Figure 11: I/O Address Space
4.5
VGA Addressing
The PEB383 supports VGA addressing. The VGA_EN bit in the
“PCI Bridge Control and Interrupt
controls the response by the bridge to both VGA frame buffer addresses and to VGA register
addresses. If the VGA Enable bit is set, the bridge decodes and forwards memory accesses to VGA
frame buffer addresses and I/O accesses to VGA registers from the PCIe Interface to the PCI Interface
(and block forwarding from PCI to PCIe of these same accesses).
The VGA_16BIT_EN bit in the
“PCI Bridge Control and Interrupt Register”
selects between 10-bit
and 16-bit VGA I/O address decoding, and is applicable when the VGA Enable bit is 1.
VGA memory addresses are 0x0A_0000 through 0x0B_FFFF
Secondary Interface
0x0_C000 – 0x0_FFFF
0x0_B000 – 0x0_BFFF
0x0_A000 – 0x0_AFFF
0x0_9000 – 0x0_9FFF
0x0_8000 – 0x0_8FFF
0x0_0000 – 0x0_7FFF
Primary Interface
Downstream
Upstream
Secondary Interface
0x0_C000 – 0x0_FFFF
0x0_B000 – 0x0_BFFF
0x0_A000 – 0x0_AFFF
0x0_9000 – 0x0_9FFF
0x0_8000 – 0x0_8FFF
0x0_0000 – 0x0_7FFF
Primary Interface
Downstream
Upstream