SAM4L Datasheet, PDF (1146/1185 Pages) ATMEL Corporation – ATSAM ARM-based Flash MCU

ATSAM4L4/L2
Maximum SPI Frequency, Master Output
The maximum SPI master output frequency is given by the following formula:
f_SPCKMAX = MIN(f_PINMAX,_S----_P-¹---_I--_n--, -^f-^C----^L---^K----^S-₉-^P----^I---^×-----²-)
Where SPIn is the MOSI delay, USPI2 or USPI5 depending on CPOL and NCPHA. f_PINMAX is
the maximum frequency of the SPI pins. refer to the I/O Pin Characteristics section for the maxi-
mum frequency of the pins. f_CLKSPI is the maximum frequency of the CLK_SPI. Refer to the SPI
chapter for a description of this clock.
42.9.2.2
Maximum SPI Frequency, Master Input
The maximum SPI master input frequency is given by the following formula:
f_SPCKMAX
=
M I N (-----------------¹------------------,^f--^C----^L---^K----^S--^P----^I---^×-----²- )
SPIn + t_VALID
9
Where SPIn is the MISO setup and hold time, USPI0 + USPI1 or USPI3 + USPI4 depending on
CPOL and NCPHA. T_VALID is the SPI slave response time. refer to the SPI slave datasheet for
T_VALID . f_CLKSPI is the maximum frequency of the CLK_SPI. Refer to the SPI chapter for a
description of this clock.
Slave mode
Figure 42-9. USART in SPI Slave Mode with (CPOL= 0 and CPHA= 1) or (CPOL= 1 and
CPHA= 0)
SPCK
MISO
USPI6
MOSI
USPI7
USPI8
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