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Bitfields for Intel 82437VX,82439TX SDRAM control register

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Bit Description

15 - 9

reserved

8 - 6

Special SDRAM Mode Select
000 = normal mode (default)
001 = enable NOP command
010 = enable All Banks Precharge command
011 = enable Mode Register Command
100 = enable CBR Cycle
101 = reserved
110 = reserved
111 = reserved

5

(82437VX) reserved

5

(82439TX) RAS# to CAS# Override
0 = RAS# to CAS# delay determined solely by CAS# latency setting
1 = and CAS# latency=0, RAS# to CAS# is delayed 2 HCLKs

4

CAS# latency
0 = latency is 3
1 = latency is 2 for all SDRAM cycles

3

RAS# precharge and refresh timing
0 = slower
1 = faster

2

reserved

1

(82437VX) reserved

1

(82439TX) 64-Mbit Technology Enable
0 = supports 64M-bit EDO/FPM devices only
1 = supports 64M-bit SDRAM devices

0

reserved

See Also:

 #01099,#01108,#01112