Intel PXA255 - Manual (Page 556)

16-16 Intel® PXA255 Processor Developer’s Manual
Network SSP Serial Port
SSCR1[TTELP] can only be set to 1 in PSP mode if the SSP is a slave to frame. If SSCR1[TTE] is
1 and SSCR1[TTELP] is 1 and the SSP is a slave to frame, SSPTXD is driven at the same clock
edge that the MSB is driven. SSPTXD is Hi-Z two clock edges after the clock edge that starts the
LSB. This occurs even if the SSP is a master of clock and this clock edge does not appear on the
SSPSCLK. If the SSP is a slave of clock, then the device driving SSPSCLK must provide another
clock edge.
Figure 16-17 shows the pin timing for this mode.
Figure 16-16. PSP mode with SSCR1[TTE]=1 and SSCR1[TTELP]=0 (master to frame)
A9979-01
MSB
Undefined Undefined
T1 T2 T3 T4
LSB
MSB LSB
T6 T5
SSPSCLK
(when SCMODE = 0)
SSPSCLK
(when SCMODE = 1)
SSPSCLK
(when SCMODE = 2)
SSPSCLK
(when SCMODE = 3)
SSPSFRM
(when SFRMP = 1)
SSPSFRM
(when SFRMP = 0)
SSPTXD
SSPRXD
Figure 16-17. PSP mode with SSCR1[TTE]=1 and SSCR1[TTELP]=1 (must be slave to frame)
A9980-01
MSB
Undefined Undefined
T1 T2 T3 T4
LSB
MSB LSB
T6 T5
SSPSCLK
(when SCMODE = 0)
SSPSCLK
(when SCMODE = 1)
SSPSCLK
(when SCMODE = 2)
SSPSCLK
(when SCMODE = 3)
SSPSFRM
(when SFRMP = 1)
SSPSFRM
(when SFRMP = 0)
SSPTXD
SSPRXD