AN2682 - Application note

STR750 implementation example

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4

STR750 implementation example

4.1

Hardware implementation

The CPLD and STR750 SSP connections are illustrated in Figure 9.

Figure 9.

MAX3000A and STR750 SSP connections

4.2

STR750 firmware description

For the STR750, the DMA is used instead of the interrupt method. That makes the software

more simple and, since the DMA automatically transfers the data from peripheral to memory

and from memory to peripheral there is no CPU load.

The STR750 SSP peripheral is configured in SPI Motorola mode.

TCLK

TDI

SCK

TDO

TMS

VCCIO

VCCIO

VCCINT

VCCINT

Gnd

Gnd

Gnd

Gnd

Gnd

R

E

Start

CLK

MISO

MOSI

SCLK

Conf

WSo

SDo

WSi

SDi

Gnd

32

7

38

13

15

35

3

23

10

17

22

30

36

42

44

1

43

2

4

5

6

8

9

11

12

14

16

3.3 V

S0.MISO

S0.MOSI

S0.SCLK

P2.19

32

81

77

76

78

31

P2.18

PWM1

I2S Audio device

Left in HiZ input state

Left in HiZ input state

1

2

3

4

5

6

7

8

9

10

TCLK

Gnd

TDO

Vcc

TMS

TDI

Gnd

NC

NC

NC