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WM8581
w
PP Rev 1.0 March 2006
19
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
2:0 READMUX
[2:0]
000
Determines which status register
is to be read back:
000 = Error Register
001 = Channel Status Register 1
010 = Channel Status Register 2
011 = Channel Status Register 3
100 = Channel Status Register 4
101 = Channel Status Register 5
110 = S/PDIF Status Register
3 CONTREAD
0
Continuous Read Enable.
0 = Continuous read-back mode
disabled
1 = Continuous read-back mode
enabled
R52
READBACK
34h
4 READEN
0 Read-back mode enable.
0 = read-back mode disabled
1 = read-back mode enabled
Table 9 Read-back Control Register
The 3-wire interface readback protocol is shown below. Note that the SDO pin is tri-state unless CSB
is held low; therefore CSB must be held low for the duration of the read.
Figure 7 3-Wire SPI Compatible Interface Continuous Readback
If CONTREAD is set to zero, the user can read back directly from the register by writing to the
register address, to which the device will respond with data. The protocol for this system is shown in
Figure 8 below.
Figure 8 3-Wire SPI Compatible Control Interface Non-Continuous Readback