VT6516 datasheet(45/73 Pages) ETC

45 / 73 page

VIA Technologies, Inc.

Preliminary VT6516 Datarsheet

-45-

02H

SDRAM Operation Mode:

For the bits [2:0], the operation modes are defined as follows:

3’b000: Normal SDRAM Mode

3’b001: NOP Command Enable

3’b010: Precharge All Banks

3’b011: MSR Enable (Mode Register Set Enable)

3’b100: CBR Refresh Cycle Enable

others: idle for power-up

For the bit [3], it is called REFRESH_EN, defined as follows:

0: turn off hardware refresh cycle (default)

1: turn on hardware refresh cycle

After the last refresh operation issued by software in the

initialization cycle, software should enable the bit “REFRESH_EN”

immediately to notify SDRAM control module ‘sdramctl’ to start

generating refresh cycle periodically.

The initialization of SDRAM control module is illustrated as

follows:

SDRAMTYPE ß 0 : 16Mb

CL ß 1 : read latency = 2

(3) delay 1

(4) RSDM ß 1 : NOP

(5) delay 1

(6) RSDM ß 2 : Precharge

(7) delay 1

(8) loop 7 times

RSDM ß 4 : Refresh

delay 1

RSDM ß 1 : NOP

delay 1

(9) RSDM ß 0CH : Refresh & turn on hardware refresh

(10) delay 1

(11) RSDM ß 0BH : Mode Register Set Enable

(12) delay 1

(13) RSDM ß 08H : Normal SDRAM Mode

(14) END0A ß 0x04 : DIM bank 0 ending address = 32MB

(15) END1A ß 0x08 : DIM bank 1 ending address = 64MB

(16) END2A ß 0x0C : DIM bank 2 ending address = 96MB

(17) END3A ß 0x10 : DIM bank 3 ending address = 128MB

RSDM

[3:0]

R/W

03H

Bits [27:23] of DIMM Bank 0 Ending Address

For the case that there are two 32MB SDRAM modules plugged in

DIMM slot 0 and two 16MB SDRAM modules plugged in DIMM

slot 1, assign the registers as follows

END0A = 04H to indicate the ending address of DIMM Bank 0 is at

2^25 (32MB)

END1A = 08H to indicate the ending address of DIMM Bank 1 is at

2^26 (64MB)

END2A = 0AH to indicate the ending address of DIMM Bank 0 is at

2^26+2^24 (80MB)

END3A = 0CH to indicate the ending address of DIMM Bank 0 is at

2^26+2^25 (96MB)

END0A

[4:0]

R/W

04H

Bits [27:23] of DIMM Bank 1 Ending Address

(see END0A)

END1A

[4:0]

R/W

05H

Bits [27:23] of DIMM Bank 2 Ending Address

(see END0A)

END2A

[4:0]

R/W

06H

Bits [27:23] of DIMM Bank 3 Ending Address

(see END0A)

END3A

[4:0]

R/W

VT6516 Datasheet(PDF) 45 Page - List of Unclassifed Manufacturers

VT6516 Datasheet(HTML) 45 Page - List of Unclassifed Manufacturers

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73

Datasheet Download

Link URL