Information

S E T E X S P C
C L E A R E X S P C
Figure 40-19. Extended Space Operation
40.7.4.2 EXSPC Operation in FSK Mode
In FSK mode, the modulator continues to count carrier out clocks, alternating between
the primary and secondary registers at the end of each modulation period.
To calculate the length of an extended space in FSK mode, one needs to know whether
MSC[EXSPC] bit was set on a primary or secondary modulation period, as well as the
total number of both primary and secondary modulation periods completed while
MSC[EXSPC] bit is high. A status bit for the current modulation is not accessible to the
CPU. If necessary, software should maintain tracking of the current modulation cycle
(primary or secondary). The extended space period ends at the completion of the space
period time of the modulation period during which MSC[EXSPC] bit is cleared.
If MSC[EXSPC] bit was set during a primary modulation cycle, use the equation:
t
exspace
= (t
space
)
p
+ (t
mark
+ t
space
)
s
+ (t
mark
+ t
space
)
p
+...
Where the subscripts p and s refer to mark and space times for the primary and secondary
modulation cycles.
If MSC[EXSPC] bit was set during a secondary modulation cycle, use the equation:
t
exspace
= (t
space
)
s
+ (t
mark
+ t
space
)
p
+ (t
mark
+ t
space
)
s
+...
40.8 CMT Interrupts and DMA
The CMT generates an Interrupt request or a DMA transfer request according to
MSC[EOCIE], MSC[EOCF], DMA[DMA] bits.
Table 40-18. DMA Transfer Request x CMT Interrupt Request
MSC[EOCF] DMA[DMA] MSC[EOCIE] DMA transfer request CMT interrupt request
0 X X 0 0
1 X 0 0 0
1 0 1 0 1
1 1 1 1 0
Chapter 40 Carrier Modulator Transmitter (CMT)
K10 Sub-Family Reference Manual, Rev. 6, Nov 2011
Freescale Semiconductor, Inc. 1057