CS8920A Ver la hoja de datos (PDF) - Cirrus Logic
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CS8920A Datasheet PDF : 144 Pages
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CS8920A
EEPROM. If configuration data are not stored in
the EEPROM, the CS8920A terminates initiali-
zation from EEPROM and operates using its
default configuration (See Table 3.3). Note: the
default configuration leaves the CS8920A in a
PnP inactive state; it can then only be accessed
through the PnP configuration and data ports. If
configuration data are stored in EEPROM, the
CS8920A automatically loads all configuration
data stored in the Reset Configuration Block into
its internal PacketPage registers.
EEPROM Readout Completion
Once all the configuration data are transferred to
the appropriate PacketPage registers, the
CS8920A adds the sum of the data bytes it read
to the 2’s complement checksum at the end of
the configuration data to verify the Reset Con-
figuration Block’s data are valid. If the resulting
total is 0, the readout is considered valid. Other-
wise, the CS8920A initiates a partial reset to
restore the default configuration.
If the readout is valid, the EEPROMOK bit
(Register 16, SelfST, bit A) is set. EEPROMOK
is cleared if a checksum error is detected. In this
case, the CS8920A performs a partial reset and
is restored to its default. Once initialization is
complete (configuration loaded from EEPROM
or reset to default configuration) the INITD bit is
set (Register 16, SelfST, bit 7).
3.6 Programming the EEPROM
After initialization, the host can access the
EEPROM through the CS8920A by writing one
of seven commands to the EEPROM Command
register (PacketPage base + 0040h). Figure 3.2
shows the format of the EEPROM Command
register.
EEPROM Commands
The seven commands used to access the
EEPROM are: Read, Write, Erase, Erase/Write
Enable, Erase/Write Disable, Erase-All, and
Write-All. They are described in Table 3.7.
EEPROM Command Execution
During the execution of a command, the two Op-
code bits, followed by six bits of address (for a
’C46 or ’CS46) or eighth bits of address (for a
’C56, ’CS56, ’C66 or ’CS66), are shifted out of
the CS8920A, into the EEPROM. If the com-
mand is a Write, the data in the EEPROM Data
register (PacketPage base + 0042h) follows. If
Command
Read Register
Write Register
Erase Register
Erase/Write Enable
Opcode
(bits 9,8)
1,0
0,1
1,1
0,0
Erase/Write Disable 0,0
0,0
Erase-All Registers 0,0
0,0
Write-All Registers 0,0
0,0
EEPROM Address
(bits 7 to 0)
word address
word address
word address
XX11-XXXX
11XX-XXXX
XX00-XXXX
00XX-XXXX
XX10-XXXX
10XX-XXXX
XX01-XXXX
01XX-XXXX
Data EEPROM Type
yes all
yes all
no all
no ’CS46, ’C46
no ’CS56, ’C56, ’CS66, ’C66
no ’CS46, ’C46
no ’CS56, ’C56, ’CS66, ’C66
no ’CS46, ’C46
no ’CS56, ’C56, ’CS66, ’C66
yes ’CS46, ’C46
yes ’CS56, ’C56, ’CS66, ’C66
Execution Time
25 µs
10 ms
10 ms
9 µs
9 µs
9 µs
9 µs
10 ms
10 ms
10 ms
10 ms
Table 3.7. EEPROM Commands
DS238PP2
23
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