WM8973-EV1M
w
Rev 1.0, February 2005
10
WM8973 OPERATION
SOFTWARE CONTROL
There are two possible serial software control modes that may be selected to operate the
WM8973. The standard SPI user interface is a 3-wire solution with the second option being
a 2-wire solution.
3-WIRE MODE
To operate the WM8973 in SPI (3-wire) mode, jumper switch SW4 must be set so that pins
1 and 2 are SHORT. The 3-wire serial interface then becomes active on pins 30(CSB),
31(SDIN) and 32(SCLK). The serial interface on the board can be connected to a PC via the
printer port or any other standard parallel port. The port used can be selected through the
software provided. The software supplied with this kit gives the user access to all the
possible features provided by the WM8973. The 3-wire latch, data and clock lines may also
be connected to the board via the test points TP2 (CSB), TP4 (SDIN) and TP3 (SCLK).
Please refer to the WM8973 datasheet for full details of the serial interface timing and all
register features.
CSB
SCLK
SDIN
B15
B6
B7
B8
B9
B10
B11
B12
B13
B14
B1
B2
B3
B4
B5
B0
Figure 2 3-Wire Serial Interface
2-WIRE MODE
To operate the WM8973 in 2-wire mode, jumper switch SW4 must be set so that pins 2 and
3 are SHORT. The 2-wire serial interface becomes active on pins 31(SDIN) and 32(SCLK).
The serial interface on the board can be connected to a PC via the printer port or any other
standard parallel port.
Note: a bi-directional parallel port is required for 2-wire
operation
1
.
The 2-wire data and clock lines may also be connected to the board via the test
points TP4 (SDIN) and TP3 (SCLK).
When used in 2-wire mode, the WM8973 has two possible addresses (0011010 [0x34h] or
0011011 [0x36h]) that are selectable by pulling CSB low or high. If connecting a probe to the
Test Points it must be noted that the CSB line is pulled high on the WM8973 evaluation
board selecting address 0011011. CSB must be pulled low or driven low through the software
writes if address 0011010 is used (as is done in the WM8973-EV1S software provided).
SDIN
SCLK
ACK
R ADDR
ACK
DATA B15-8
STOP
START
DATA B7-0
R/W
ACK
Figure 3 2-Wire Serial Interface
Note:
1
If the 2-wire mode does not operate as expected, the likely cause is the configuration
of the parallel port interface mode. Check that the port is configured for bi-directional
communication. Most PCs allow the parallel port to be configured in the BIOS settings during
initial PC power up.
Содержание WM8973-EV1B
Страница 1: ...WM8973 EV1M Evaluation Board User Handbook Rev 1 0...
Страница 3: ...WM8973 EV1M w Rev 1 0 February 2005 3 EVALUATION SUPPORT 44 IMPORTANT NOTICE 45 ADDRESS 45...
Страница 21: ...WM8973 EV1M w Rev 1 0 February 2005 21 SCHEMATIC LAYOUT Figure 13 Functional Diagram...
Страница 22: ...WM8973 EV1M w Rev 1 0 February 2005 22 Figure 14 Digital Input...
Страница 23: ...WM8973 EV1M w Rev 1 0 February 2005 23 Figure 15 Software Control...
Страница 24: ...WM8973 EV1M w Rev 1 0 February 2005 24 Figure 16 Level Shift...
Страница 25: ...WM8973 EV1M w Rev 1 0 February 2005 25 Figure 17 Analogue Input...
Страница 26: ...WM8973 EV1M w Rev 1 0 February 2005 26 Figure 18 WM8973...
Страница 27: ...WM8973 EV1M w Rev 1 0 February 2005 27 Figure 19 Analogue Output...
Страница 28: ...WM8973 EV1M w Rev 1 0 February 2005 28 Figure 20 Power...
Страница 29: ...WM8973 EV1M w Rev 1 0 February 2005 29 WM8973 EV1B PCB LAYOUT Figure 21 Top Layer Silkscreen...
Страница 30: ...WM8973 EV1M w Rev 1 0 February 2005 30 Figure 22 Top Layer...
Страница 31: ...WM8973 EV1M w Rev 1 0 February 2005 31 Figure 23 Bottom Layer...
Страница 32: ...WM8973 EV1M w Rev 1 0 February 2005 32 Figure 24 Bottom Layer Silkscreen...
