Intel 440GX manual 13. Flash Vpp Recommendations, Design Checklist, Write Protection

Models: 440GX

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Table 3-13. Flash Vpp Recommendations

Design Checklist

(WP# pin not available on 8-Mbit 44-lead PSOP. In this package, treat as if the WP# pin is internally tied low, effectively eliminating the last row of the table below.)

Use either A16 or A17 inversion for both the 2Mbit or 4Mbit to differentiate between recovery and normal modes.

If migrating a BV design to the lower cost B5 device, Application Brief AB-65 “Migrating SmartVoltage Boot Block Flash Designs to Smart 5 Flash” is available (Order#292194).

Table 3-13. Flash Vpp Recommendations

VPP

RP#

WP#

Write Protection

 

 

 

 

VIL

X

X

All Blocks Locked (Programming)

 

 

 

 

VPPLK

VIL

X

All Blocks Locked (All operations)

 

 

 

 

VPPLK

VHH

X

All Blocks Unlocked (All operations)

 

 

 

 

VPPLK

VIH

VIL

Boot Block Locked (Programming)

 

 

 

 

VPPLK

VIH

VIH

All Blocks Unlocked (All operations)

 

 

 

 

NOTES:

1.VPPLK is specified at 1.5V(maximum).

2.VIL is specified at logic low.

3.VIH is specified at logic high.

4.VHH is specified at 12V±5%.

Use SUSA# to drive the flash RP# pin into the deep power-down mode when system is in the suspend states.

(SUSA# Alternative) Use system “POWEROK” or “POWERGOOD” signal to drive flash RP# to keep device in deep power down during power-up only (write protection). For systems not needing power saving modes.

Connect BYTE# to GND for byte-wide mode operation if x16 device is used.

Use a 0.01mf - 0.1mf ceramic capacitor connected between each Vcc and GND, and between its Vpp and GND. These high frequency, inherently low inductance capacitors should be placed as close as possible to the package leads.

Add information on how BIOSCS# elevates the need for control logic and GPO[x] control on WE#

Add information on ISA load consideration and the reduction of the X-bus drivers/control

Figure 3-7illustrates the recommended layout for Intel’s flash devices in desktop designs:

Intel®440GX AGPset Design Guide

3-27

Page 87
Image 87
Intel 440GX manual 13. Flash Vpp Recommendations, Design Checklist, Write Protection