Cirrus Logic CS5378 - Manual (Page 27)

CS5378
DS639F3 27
The maximum number of bytes that will be written
for a single configuration is less than 2 KByte
(16 Kbit), including command overhead:
Supported serial configuration EEPROMs are
SPI mode 0 (0,0) compatible, 16-bit addresses, 8-
bit data, larger than 2 KByte (16 KBit). ATMEL
AT25640, AT25128, or similar serial EEPROMs
are recommended.
8.4 EEPROM Configuration Commands
A summary of available EEPROM commands is
shown in Table 7.
Write DF Register - 0x01
This EEPROM command writes a data value to the
specified digital filter register. Digital filter regis-
ters control hardware peripherals and filtering
functions. See “Digital Filter Registers” on page 71
for the bit definitions of the digital filter registers.
Sample Command:
Write digital filter register 0x00 with data value
0x060431. Then write 0x20 with data 0x000240.
01 00 00 00 06 04 31
01 00 00 20 00 02 40
Write FIR Coefficients - 0x02
This EEPROM command writes custom coeffi-
cients for the FIR1 and FIR2 filters. The first two
data words set the number of FIR1 and FIR2 coef-
ficients to be written. The remaining data words are
the concatenated FIR1 and FIR2 coefficients.
A maximum of 255 coefficients can be written for
each FIR filter, though the available digital filter
computation cycles will limit their practical size.
See “FIR Filter” on page 44 for more information
about FIR filter coefficients.
Sample Command:
Write FIR1 coefficients 0x00022E, 0x000771 then
FIR2 coefficients 0xFFFFB9, 0xFFFE8D.
02 00 00 02 00 00 02
00 02 2E 00 07 71 FF FF B9 FF FE 8D
Write IIR Coefficients - 0x03
This EEPROM command writes custom coeffi-
cients for the two stage IIR filter. The IIR architec-
ture and number of coefficients is fixed, so eight
data words containing coefficient values always
immediately follow the command byte. The IIR co-
efficient write order is: a11, b10, b11, a21, a22,
b20, b21, and b22. See “IIR Filter” on page 52 for
more information about IIR filter coefficients.
Figure 16. 8 Kbyte EEPROM Memory Organization
0000h
1FFFh
EEPROM
Manufacturing
Information
EEPROM
Command and
Data Values
Mfg Header
8-bit Command
0010h
N x 24-bit Data
8-bit Command
N x 24-bit Data
. . .
Table 6. Maximum EEPROM Configuration
Memory Requirement Bytes
Digital Filter Registers (12) 84
FIR Coefficients (255+255) 1537
IIR Coefficients (3+5) 25
‘Filter Start’ Command 1
Total Bytes 1647