Spi timing characteristics – Digi NS9215 User Manual

Page 443

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S E R I A L C O N T R O L M O D U L E : S P I

SPI timing characteristics

www.digiembedded.com

443

Register

Register bit
assignment

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

S P I t i m i n g c h a r a c t e r i s t i c s

These are the guaranteed timing parameters for all four SPI clocking modes.

SPI master timing
parameters

13

12

11

10

9

8

7

6

5

4

3

2

1

0

15

14

31

29

28

27

26

25

24

23

22

21

20

19

18

17

16

30

Not used

Not used

TX_ IDLE RX_IDLE

Bits

Access

Mnemonic

Reset

Description

D31:02

R/W

Not used

0

Write this field to 0.

D01

R/W1TC

TX_IDLE

0

Transmit idle
Indicates that the transmitter has moved from the active
state to the idle state. The transmitter moves from the active
state to the idle state when the transmit FIFO is empty and
the transmitter is not actively shifting out data.

D00

R/W1TC

RX_IDLE

0

Receive idle

Indicates that the receiver has moved from the active state
to the idle state. The receiver moves from the active state to
the idle state when a start bit has not been received within 4
bit periods of the previous stop bit.

Parm

Description

Min

Max

Unit

Notes

S1

CS# falling to CLK rising

1

clock

1

S2

CLK period low time

12

13

ns

2

S3

CLK period high time

12

13

ns

2

S4

Data output setup to CLK rising

11

ns

3

S5

Data output hold from CLK rising

11

ns

3

S6

Data input setup to CLK rising

10

ns

4

S7

Data input hold from CLK rising

0

ns

4

S8

CLK falling to CS# rising

1

clock

1

S9

CS# deassertion time

4

clock

1

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