
76
32117DS–AVR-01/12
AT32UC3C
Figure 7-12. SPI Master Mode With (CPOL= 0 and NCPHA= 1) or (CPOL= 1 and NCPHA= 0)
Note:
1. These values are based on simulation and characterization of other AVR microcontrollers manufactured in the same pro-
cess technology. These values are not covered by test limits in production.
Maximum SPI Frequency, Master Output
The maximum SPI master output frequency is given by the following formula:
Where
is the MOSI delay, SPI2 or SPI5 depending on CPOL and NCPHA.
is the
maximum frequency of the SPI pins. Please refer to the I/O Pin Characteristics section for the
maximum frequency of the pins.
Maximum SPI Frequency, Master Input
The maximum SPI master input frequency is given by the following formula:
Where
is the MISO setup and hold time, SPI0 + SPI1 or SPI3 + SPI4 depending on
CPOL and NCPHA.
is the SPI slave response time. Please refer to the SPI slave
datasheet for
.
SPI3
SPI4
MISO
SPCK
MOSI
SPI5
Table 7-48.
Symbol
Parameter
Conditions
Min
Max
Units
SPI0
MISO setup time before SPCK rises
external
capacitor =
40pF
28.5+ (tCLK_SPI)/2
ns
SPI1
MISO hold time after SPCK rises
0
ns
SPI2
SPCK rising to MOSI delay
10.5
ns
SPI3
MISO setup time before SPCK falls
28.5 + (t
CLK_SPI)/2
ns
SPI4
MISO hold time after SPCK falls
0
ns
SPI5
SPCK falling to MOSI delay
10.5
ns
fSPCKMAX
MIN fPINMAX
1
SPIn
------------
(,
)
=
SPIn
fPINMAX
fSPCKMAX
1
SPIn tVALID
+
------------------------------------
=
SPIn
tVALID