Rev. D
|
Page 44 of 56
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November 2008
ADSP-21367/ADSP-21368/ADSP-21369
SPI Interface—Slave
Table 42. SPI Interface Protocol—Slave Switching and Timing Specifications
Parameter
Min
Max Unit
Timing Requirements
t
SPICLKS
Serial Clock Cycle
4 × t
PCLK
– 2
ns
t
SPICHS
Serial Clock High Period
2 × t
PCLK
– 2
ns
t
SPICLS
Serial Clock Low Period
2 × t
PCLK
– 2
ns
t
SDSCO
SPIDS Assertion to First SPICLK Edge, CPHASE = 0 or CPHASE = 1
2 × t
PCLK
ns
t
HDS
Last SPICLK Edge to SPIDS Not Asserted, CPHASE = 0
2 × t
PCLK
ns
t
SSPIDS
Data Input Valid to SPICLK Edge (Data Input Setup Time)
2
ns
t
HSPIDS
SPICLK Last Sampling Edge to Data Input Not Valid
2
ns
t
SDPPW
SPIDS Deassertion Pulse Width (CPHASE = 0)
2 × t
PCLK
ns
Switching Characteristics
t
DSOE
SPIDS Assertion to Data Out Active
0
6.8
ns
t
DSOE
1
SPIDS Assertion to Data Out Active (SPI2)
0
8
ns
t
DSDHI
SPIDS Deassertion to Data High Impedance
0
6.8
ns
t
DSDHI
1
SPIDS Deassertion to Data High Impedance (SPI2)
0
8.6
ns
t
DDSPIDS
SPICLK Edge to Data Out Valid (Data Out Delay Time)
9.5
ns
t
HDSPIDS
SPICLK Edge to Data Out Not Valid (Data Out Hold Time)
2 × t
PCLK
ns
t
DSOV
SPIDS Assertion to Data Out Valid (CPHASE = 0)
5 × t
PCLK
ns
1
The timing for these parameters applies when the SPI is routed through the signal routing unit. For more information, see the
ADSP-21368 SHARC Processor Hardware
Reference
, “Serial Peripheral Interface Port” chapter.
Figure 35. SPI Slave Timing
t
H
S
P ID
S
t
D D
S
P I D
S
t
D
S
D H I
L
S
B
M
S
B
M
S
B VALID
t
D
S
O E
t
D D
S
P I D
S
t
H D
S
P ID
S
MI
S
O
(OUTPUT)
MO
S
I
(INPUT)
t
S S
P I D
S
SPIDS
(INPUT)
S
PICLK
(CP = 0)
(INPUT)
S
PICLK
(CP = 1)
(INPUT)
t
S
D
S
C O
t
S
P I C H
S
t
S
P I C L
S
t
S
P I C L
S
t
S
P I C L K
S
t
H D
S
t
S
P I C H
S
t
S S
P I D
S
t
H
S
P ID
S
t
D
S
D H I
L
S
B VALID
M
S
B
M
S
B VALID
t
D
S
O E
t
D D
S
P I D
S
MI
S
O
(OUTPUT)
MO
S
I
(INPUT)
t
S S
P I D
S
L
S
B VALID
L
S
B
CPHA
S
E = 1
CPHA
S
E = 0
t
S
D P P W
t
D
S
O V
t
H D
S
P ID
S