External Memory Controller (EMC)
Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
Freescale Semiconductor
21-79
shows how data sampling is controlled by the UPM.
Figure 21-42. UPM Read Access Data Sampling
21.4.4.4.8
LGPL[5:0] Signal Negation (LAST)
When the LAST bit is read in a RAM word, the current UPM pattern is terminated at the end of the current
cycle. On the next cycle (following LAST), all of the UPM signals are negated unconditionally (driven to
logic 1), unless there is a back-to-back UPM request pending. In this case, the signal values for the cycle
(following the cycle in which the LAST bit was set) are taken from the first RAM word of the pending
UPM routine.
21.4.4.4.9
The Wait Mechanism (WAEN)
The WAEN bit in the RAM array word can be used to enable the UPM wait mechanism in selected UPM
RAM words. If the UPM reads a RAM word with WAEN set, the external UPWAIT signal is sampled and
synchronized by the memory controller as if it were an asynchronous signal. The WAEN bit is ignored if
LAST = 1 in the same RAM word.
Synchronization of UPWAIT starts at the rising edge of the bus clock and takes at least 1 bus cycle to
complete. If UPWAIT is asserted and WAEN = 1 in the current UPM word, the UPM is frozen until
UPWAIT is negated. The value of external signals driven by the UPM remains as indicated in the previous
RAM word. When UPWAIT is negated, the UPM continues normal functions. Note that during WAIT
cycles, the UPM does not handle data.
shows how the WAEN bit (in the word read by the UPM) and the UPWAIT signal are used
to hold the UPM in a particular state until UPWAIT is negated. As the example shows, the LCSx and
LGPL1 states and the WAEN value are frozen until UPWAIT is recognized as negated. WAEN is typically
set before the line that contain UTA = 1. Note that if WAEN and NA are both set in the same RAM word,
NA causes the burst address to increment once as normal regardless of whether UPM freezes or not.
To internal
data bus
LCLK
UPM read AND GPL4xDIS = 1 AND DLT3 = 1
LAD[23:0]
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Содержание Symphony DSP56724
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Страница 52: ...Symphony DSP56724 DSP56725 Multi Core Audio Processors Rev 0 2 30 Freescale Semiconductor Signal Descriptions ...
Страница 112: ...Symphony DSP56724 DSP56725 Multi Core Audio Processors Rev 0 7 12 Freescale Semiconductor Clock Generation Module CGM ...
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