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July 17, 2002
125
Serial Write-protection PLD Data
Figure 26:
Write Protection TSSOP-24 CUPL Source Code
Name
wrprotpd;
PartNo
0;
Date
8/09/00;
Revision 3;
Designer Transmeta;
Company
Transmeta;
Assembly 1;
Location 1;
Format
j;
/* Use JEDEC output format */
Device
G22V10CP;
/* This is the code for a 24-pin TSSOP package. */
/* The powerdown function on pin 4 is implied by */
/* this description. */
/**********************************************************************
*
* This device protects against writes and erases to the serial flash
* when the WP pin is asserted.
It works by forcing the chip select
* to negate when a write or erase command is detected.
The WPNEG
* pin causes the WP input to be inverted in case WP is active-low on
* the circuit board.
Two chip selects are handled for the case of
* two half-size serial ROMs.
*
* A select input pin is used to choose between Atmel and Macronix.
* The reason this is needed is the opcodes between the two parts are
* similar enough to require detection of all 8 bits of the opcode.
* If the chip select is negated after the 8th bit of the opcode, the
* flash device will execute the command with bogus address and data.
* The select input allows write or erase opcodes to be detected in as
* few as two bits.
*
* This design file is written for the CUPL programmable logic
* compiler.
A free, functional, demo version of the compiler is
* available from http://www.logicaldevices.com/.
*
**********************************************************************/
/*
*
Input pins
*
*
All unused inputs should be tied high or low on the circuit board.
*
Active-low pins are denoted by the ! prefix.
After the input and
*
output sections of this file, all syntax refers to the logical
*
level of a pin and not its physical level.
*/
PIN
1 =
CKIN;
/* Serial flash clock */
PIN
2 =
WP;
/* Write protect */
PIN
3 =
DIN;
/* Serial flash data input */
/* PIN 4 = PD;
Powerdown pin, implied by device selection */
PIN
7 =
WPNEG;
/* Write protect negate: */
/*
Tie low
if WP is active-high */
/*
Tie high if WP is active-low */
PIN
8 =
SEL;
/* Select type of flash: */
/*
High = Macronix */
/*
Low
= Atmel */
PIN
5 = !CS0IN;
/* Intercepted serial flash chip selects.
If */
PIN
6 = !CS1IN;
/*
one is unused, it should be tied high. */
Содержание Crusoe TM5500
Страница 1: ...TM5500 TM5800 System Design Guide July 17 2002...
Страница 6: ...July 17 2002 6 List of Tables...
Страница 8: ...July 17 2002 8 List of Figures...
Страница 50: ...July 17 2002 50 Processor Power Supplies and Power Management...
Страница 110: ...July 17 2002 110 System Design Considerations...
Страница 122: ...July 17 2002 122 System Design Checklists...
Страница 128: ...July 17 2002 128 Serial Write protection PLD Data...
Страница 130: ...July 17 2002 130 Index...