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AS3953

Datasheet - D e t a il e d D es c r i pt io n

Word Address Byte.

Both proprietary commands related to EEPROM (Read and Write) use Word Address byte to define the address of EEPROM word that is

accessed. Seven MSB bits of the Address Byte are used to define the address, while the last bit is “don’t care”.

Note:

The valid range for the Word Address byte is from 0000 000xb to 0011 111xb (EEPROM words from 00h to 1Fh).

Read EEPROM.

The

Read EEPROM command is used to read data from the EEPROM. The request information field contains the following three bytes –

- Command code byte (02h)

- Address of the first word to be read

- Number of words to be read

Table below defines coding of

Read EEPROM command information field.

If the request is normally processed, the reply information field contains the status word

90h followed by the data. In case of error, the information

field only contains the error status byte. The following rules apply:



In case the number of words to be read is higher than 8, first eight words are read.



In case the read protected word (its read lock bit is set) is accessed, an all ‘0’ data is sent out.



In case the reading starts at valid address and the number of words to read is such that the reading would be done beyond the EEPROM

addressing space, all ‘0’ data is returned for non-existing addresses.



In case the reading starts at non-existing address, error information field is returned.

Table below defines the coding of the AS3953 reply information field to

Read EEPROM command, if command is normally processed.

Table below defines the coding of the AS3953 reply information field to

Read EEPROM command, in case of an error.

Write EEPROM.

The

Write EEPROM command is used to write one EEPROM word (32 bits). The request information field contains 6 bytes –

- Command code byte (04h)

- Address of the word to be written

- Four bytes (32 bits) of data to be written

Table below defines coding of

The AS3953 reply contains one byte informing whether the writing of EEPROM was executed or whether there was an error. Prior to actual

programming of data in EEPROM, the control logic checks whether there is enough power available. This is done by performing so called power

check during which a dummy EEPROM programming is started. If the power check fails, EEPROM programming is not performed and an error

code is sent. The EEPROM programming is a time consuming operation. Therefore, if the EEPROM programming is executed, the AS3953 reply

comes after 8ms typical. Table below defines the coding of the AS3953 reply to

Write EEPROM command.

02h

Address of first word to be read Number of words (

≤ 8) to be read

1byte

1byte

1byte

90h

Data

1byte

4 to 32 bytes

Information Field

Comment

61h

Error (no diagnostic)

04h

Address of word to be written

Data

1 byte

1 byte

4 bytes

Information Field

Comment

90h

Writing is normally processed

61h

Writing is not done due to coding error

(error in parity, CRC, nonexistent address…)

62h

Writing is not done since the word is locked

64h

Writing is not done due to power check fail