TAS3108DCPR datasheet(33/63 Pages) TI1

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TAS3108, TAS3108IA

AUDIO DIGITAL SIGNAL PROCESSORS

SLES152B – OCTOBER 2005 – REVISED NOVEMBER 2007

Once the microprocessor program memory has been loaded, it cannot be reloaded until the

TAS3108/TAS3108IA has been reset.

If an error is encountered, TAS3108/TAS3108IA terminates its memory-load operation, loads the default

configuration, and disables further master I2C bus operations.

If an end-of-program data block is read, the TAS3108/TAS3108IA has completed the initial program load.

The I2C master mode uses the starting and ending I2C checksums to verify a proper EEPROM download.

The first 16-bit data word received from the EEPROM, the I2C checksum at subaddress 0x00, is stored

and compared against the 16-bit data word received for the last subaddress, the ending I2C checksum,

and the checksum that is computed during the download. These three values must be equal. If the read

and computed values do not match, the TAS3108/TAS3108IA sets the memory read error bits in the

status register and repeats the download from the EEPROM two more times. If the comparison check fails

the third time, the TAS3108/TAS3108IA sets the microprocessor program to the default value.

Table 6-5 shows the format of the EEPROM or other external memory load file. Each line of the file is a

byte (in ASCII format). The checksum is the summation of all the bytes (with beginning and ending

checksum fields = 00). The final checksum inserted into the checksum field is the lowest significant four

bytes of the checksum.

Example:

Given the following example 8051 data or program block (must be a multiple of 4 bytes for these blocks):

10h

20h

30h

40h

50h

60h

70h

80h

The checksum = 10h + 20h + 30h + 30h + 40h + 50h + 60h + 70h + 80h = 240h, so

the values put in the checksum fields are MS byte = 02h and LS byte = 40h.

If the checksum is > FFFFh, the 2-byte checksum field is the least-significant two bytes.

For example, if the checksum is 1D 45B6h, the checksum field is MS byte = 45h and LS byte = B6h.

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