WM8951L Wolfson Microelectronics plc, WM8951L Datasheet - Page 31
WM8951L
Manufacturer Part Number
WM8951L
Description
Stereo ADC with Microphone Input and Clock Generator
Manufacturer
Wolfson Microelectronics plc
Datasheet
1.WM8951L.pdf
(42 pages)
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Quantity
Price
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Part Number:
WM8951LGEFL
Manufacturer:
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3-WIRE (SPI COMPATIBLE) SERIAL CONTROL MODE
The WM8951L can be controlled using a 3-wire serial interface. SDIN is used for the program data,
SCLK is used to clock in the program data and CSB is use to latch in the program data. The 3-wire
interface protocol is shown in Figure 23.
Figure 23 3-Wire Serial Interface
Notes:
1.
2.
3.
2-WIRE SERIAL CONTROL MODE
The WM8951L supports a 2-wire serial interface. The WM8951L has one of two slave addresses that
are selected by setting the state of pin 26, (CSB).
Figure 24 2-Wire Serial Interface
Notes:
1.
2.
Table 19 2-Wire MPU Interface Address Selection
To control the WM8951L on the 2-wire bus the master control device must initiate a data transfer by
establishing a start condition, defined by a high to low transition on SDIN while SCLK remains high.
This indicates that an address and data transfer will follow. All peripherals on the 2-wire bus respond
to the start condition and shift in the next eight bits (7-bit address + R/W bit). The transfer is MSB
first. The 7-bit address consists of a 6-bit base address + a single programmable bit to select one of
two available addresses for this device (see table 24). If the correct address is received and the R/W
bit is ‘0’, indicating a write, then the WM8951L will respond by pulling SDIN low on the next clock
pulse (ACK). The WM8951L is a write only device and will only respond to the R/W bit indicating a
write. If the address is not recognised the device will return to the idle condition and wait for a new
start condition and valid address.
Once the WM8951L has acknowledged a correct address, the controller will send eight data bits (bits
B15-B8). WM8951L will then acknowledge the sent data by pulling SDIN low for one clock pulse.
SCLK
SDIN
B[15:9] are Control Address Bits
B[8:0] are Control Data Bits
CSB is edge sensitive not level sensitive. The data is latched on the rising edge of CSB.
B[15:9] are Control Address Bits
B[8:0] are Control Data Bits
SCLK
SDIN
CSB
START
CSB STATE
0
1
B15
R ADDR
B14
B13
R/W
B12
B11
ACK
B10
ADDRESS
0011010
0011011
B9
DATA B15-8
B8
B7
B6
ACK
B5
B4
DATA B7-0
PD Rev 4.1 December 2007
B3
www.DataSheet4U.com
B2
ACK
B1
WM8951
B0
STOP
31