AD1845 Analog Devices, AD1845 Datasheet - Page 19

• Manufacturer Part Number: AD1845
• Description: Parallel-port 16-Bit Soundport Stereo Codec
• Manufacturer: Analog Devices

REV. B
NOTE: Placing the AD1845 in the Mode Change Enable (MCE) state is not required when changing the sample rate. However, changes to
CSS
CFS2:0
S/M
C/L
FMT
res
This register’s initial state after reset is “x000 0000.”
Clock and Data Format Register (IXA3:0 = 8)
FMT, C/L, and S/M require MCE or setting PEN = 0.
IXA3:0
8
Reserved for future expansion. Always write a zero to this bit.
Clock Source Select. This bit in conjunction with CFS2:0 selects the audio sample rate frequency. See Figure 8
Clock Frequency Divide Select. These bits in conjunction with CSS select the audio sample frequency.
below. Note: MODE2 allows a wider range of sample rate frequencies to be selected by using the Frequency
Select Register (refer to Registers 22 and 23).
Stereo/Mono Select. This bit determines how the audio data streams are formatted. Selecting stereo will result
with alternating samples representing left and right audio channels. Mono playback plays the same audio sample
on both channels. Mono capture only captures data from the left audio channel.
0
1
Companded/Linear Select. This bit selects between a linear digital representation of the audio signal or a nonlinear,
companded format for all input and output data. The type of linear PCM or the type of companded format is
defined by the FMT bits.
0
1
Format Select. This bit defines the format for all digital audio input and outputs based on the state of the C/L
bit. See Figure 9 for FMT and C/L bit settings that determine the audio data type format.
Data 7
Mono
Stereo
Linear PCM
Companded
res
FMT
0
0
1
1
CFS2
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Data 6
FMT
Figure 8. MODE1 Audio Sample Frequency Select
CFS1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Figure 9. Digital Audio Data Type
Data 5
C/L
C/L
0
1
0
1
CFS0
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
–19–
Data 4
S/M
CSS
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Audio Data Type
Linear, 8-Bit Unsigned PCM
Linear, 16-Bit Twos-Complement PCM
A-Law, 8-Bit Companded
-Law, 8-Bit Companded
Data 3
CFS2
Sample Rate
16.0
11.025
27.42857 kHz
18.9
32.0
22.05
Reserved
37.8
Reserved
44.1
48.0
33.075
8.0
5.5125
9.6
6.615
Data 2
CFS1
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
Data 1
CFS0
AD1845
Data 0
CSS