WM8734-EV1M 参数 Datasheet PDF下载

WM8734-EV1M

WM8734 OPERATION

SOFTWARE CONTROL

There are two possible serial control modes that may be selected to operate the WM8734. The

standard SPI user interface is a 3-wire solution with the second option being a 2-wire solution.

To operate the WM8734 in SPI (3-wire) mode, the jumper on link J8 must be removed leaving pins 1

and 2 OPEN. The 3-wire serial interface then becomes active on pins 18(SCLK), 17(SDIN) and

16(CSB). 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 WM8734. The

3-wire latch, data and clock lines may also be connected to the board via the test points TP3 (CSB),

TP2 (SDIN) and TP1 (SCLK).

Please refer to the WM8734 datasheet for full details of the serial interface timing and all register

features.

CSB

SCLK

SDIN

B15

B14

B13

B12

B11

B10

B9

B8

B7

B6

B5

B4

B3

B2

B1

B0

Figure 2 3-Wire Serial Interface

To operate the WM8734 in 2-wire mode, the jumper on link J8 must SHORT pins 1 and 2. The 2-wire

serial interface becomes active on pins 18(SCLK) and 17(SDIN). 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 TP2 (SDIN) and TP1 (SCLK).

When used in 2-wire mode, the WM8734 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 WM8734 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 WM8734-EV1S software provided).

SDIN

R ADDR

R/W

ACK

DATA B15-8

ACK

DATA B7-0

ACK

SCLK

START

STOP

Figure 3 2-Wire Serial Interface

Note:

1.

If the 2-wire mode is not reporting as expected then the most likely cause is that the

parallel port being used is not bi-directional. In most PC’s, the parallel port can be

configured in the BIOS settings during initial power up.

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Rev 1.2 November 2002

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