tc(SPC) +SPI clock cycle time +LSPCLK
4or LSPCLK
(SPIBRR)1) +tc(LCO) +LSPCLK cycle time
20
15
SPISIMO
SPISOMI
SPICLK
(clock polarity = 1)
SPICLK
(clock polarity = 0)
SPISIMO Data
Must Be Valid
SPISOMI Data Is Valid
19
16
14
13
12
SPISTE
(see Note A)
(2)
SM320F2812-HT
www.ti.com
SGUS062A–JUNE 2009 –REVISED APRIL 2010
6.20 SPI Slave Mode Timing
Table 6-23. SPI Slave Mode External Timing (Clock Phase = 0)(1) (2) (3)
NO. MIN MAX UNIT
12 tc(SPC)S Cycle time, SPICLK 4tc(LCO) (2) ns
tw(SPCH)S Pulse duration, SPICLK high (clock polarity = 0) 0.5tc(SPC)S – 10 0.5tc(SPC)S
13(4) ns
tw(SPCL)S Pulse duration, SPICLK low (clock polarity = 1) 0.5tc(SPC)S – 10 0.5tc(SPC)S
tw(SPCL)S Pulse duration, SPICLK low (clock polarity = 0) 0.5tc(SPC)S – 10 0.5tc(SPC)S
14(4) ns
tw(SPCH)S Pulse duration, SPICLK high (clock polarity = 1) 0.5tc(SPC) – 10 0.5tc(SPC)S
Delay time, SPICLK high to SPISOMI valid
td(SPCH-SOMI)S 0.375tc(SPC)S – 10
(clock polarity = 0)
15(4) ns
td(SPCL-SOMI)S Delay time, SPICLK low to SPISOMI valid (clock polarity = 1) 0.375tc(SPC)S – 10
Valid time, SPISOMI data valid after SPICLK low
tv(SPCL-SOMI)S 0.75tc(SPC)S
(clock polarity = 0)
16(4) ns
Valid time, SPISOMI data valid after SPICLK high
tv(SPCH-SOMI)S 0.75tc(SPC)S
(clock polarity = 1)
tsu(SIMO-SPCL)S Setup time, SPISIMO before SPICLK low (clock polarity = 0) 0
19(4) ns
tsu(SIMO-SPCH)S Setup time, SPISIMO before SPICLK high (clock polarity = 1) 0
Valid time, SPISIMO data valid after SPICLK low
tv(SPCL-SIMO)S 0.5tc(SPC)S
(clock polarity = 0)
20(4) ns
Valid time, SPISIMO data valid after SPICLK high
tv(SPCH-SIMO)S 0.5tc(SPC)S
(clock polarity = 1)
(1) The MASTER/SLAVE bit (SPICTL.2) is cleared and the CLOCK PHASE bit (SPICTL.3) is cleared.
(3) Not production tested.
(4) The active edge of the SPICLK signal referenced is controlled by the CLOCK POLARITY bit (SPICCR.6).
A. Inthe slave mode, the SPISTE signal should be asserted low at least 0.5tc(SPC) before the valid SPI clock edge and
remain low for at least 0.5tc(SPC) after the receiving edge (SPICLK) of the last data bit.

Figure 6-26. SPI Slave Mode External Timing (Clock Phase = 0)

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