ATSHA204A datasheet(9/93 Pages) MICROCHIP

9 / 93 page

On shipment from Microchip, the EEPROM contains factory test data that can be used for fixed-value

board testing. This data must be overwritten with the desired contents prior to locking the configuration

and/or data sections of the device. See the Microchip website for the document containing the specific

shipment values.

2.1.1

EEPROM Data Zone

The Data zone is 512-bytes (4 kb), is part of the EEPROM array and can be used for secure storage

purposes.

Prior to locking the configuration section using Lock(Config), the Data zone is inaccessible and can be

neither read nor written. After configuration locking, the entire Data zone can be written using the Write

command. If desired, the data to be written can be encrypted.

In the following table, “Byte Address” is the byte address within the Data zone for the first byte in the

respective slot. Because all Reads and Writes with the ATSHA204A are performed on a word (4-byte or

32-byte) basis and the word address in the table below should be used for the address parameter passed

to the Read and Write commands.

Table 2-3. Data Zone Slots

Slot

Byte Address (Hex)

Word Address (Hex)

Slot

Byte Address (Hex)

Word Address (Hex)

0x0000

0x0100

0x0040

0x0020

0x0008

0x0120

0x0048

0x0040

0x0010

0x0140

0x0050

0x0060

0x0018

0x0160

0x0058

0x0080

0x0020

0x0180

0x0060

0x00A0

0x0028

0x01A0

0x0068

0x00C0

0x0030

0x01C0

0x0070

0x00E0

0x0038

0x01E0

0x0078

2.1.2

Configuration Zone

The 88-bytes (704-bits) in the Configuration zone contain manufacturing identification data, general

device and system configuration and access restriction control values for the slots within the Data zone.

The values of these bytes can always be obtained using the Read command. The bytes of this zone are

arranged as shown in the following table.

Table 2-4. Configuration Zone

Word Byte 0

Byte 1

Byte 2

Byte 3

Default

Write Access Read

Access

0x00

SN<0:3>

01 23 xx xx

Never

Always

0x01

RevNum

xx xx xx xx

Never

Always

0x02

SN<4:7>

xx xx xx xx

Never

Always

0x03 SN<8>

Reserved

I2C_Enable

Reserved

EE 55 xx 00

Never

Always

0x04 I2C_Address

CheckMacConfig OTP Mode

Selector Mode C8 00 55 00

If Config Is

unlocked

Always

ATSHA204A

Device Organization

DS40002025A-page 9

ATSHA204A Datasheet(PDF) 9 Page - Microchip Technology

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