Woodhead SST-PFB3-ISA, Справочник по аппаратуре

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Hardware Reference Guide SST-PFB3-ISA
32 Hardware Register Details
©2004 Woodhead Software & Electronics, Division of Woodhead Canada Limited
Document Edition: 1.0, Document #: 715-0078, Template Edition: 1.1, Template #: QMS-06-045
Use, duplication or disclosure of this document or any of the information contained herein is subject to the restrictions on page ii of this document.
Bit and Value Window Size and Bank Number
BA19 BA18 BA17 BA16 BA15 BA14 BA13 BA12 8k 16k 32k 64k 128k 256k
x x 1 1 0 0 1 x 25 12 6 3 1 0
x x 1 1 0 1 0 x 26 13 6 3 1 0
x x 1 1 0 1 1 x 27 13 6 3 1 0
x x 1 1 1 0 0 x 28 14 7 3 1 0
x x 1 1 1 0 1 x 29 14 7 3 1 0
x x 1 1 1 1 0 x 30 15 7 3 1 0
x x 1 1 1 1 1 x 31 15 7 3 1 0
* x = don’t care
Table 15: Bank Address Register Bit Descriptions
Bit Name
Description
BA17-13
The card has 256k of memory accessible to the host. The Bank Address bits select which
bank of memory the host can access. For example, in 16k mode, the bank number may be
0 through 15 (or 0x0 - 0xf).
•
The primary host interface window is located in bank 0
•
BA17-BA13 represent the bank address, providing A17-A13 for shared RAM accesses
•
Bank numbers depend on the window size, which is selected using the WinSize bits.
Refer to Table 17,
Winsize Register Values , for more information.
To access any memory address in a flat address model, in any window size, set the Bank Address
bits to correspond to address bits 19-12. In C, you would write:
outport( BankSelect, addr>>12);
offset= addr & ((inport( WinSize ) <<12 ) | 0x3FFF);