Symphony DSP56724/DSP56725 Multi-Core Audio Processors, Rev. 0
21-66
Freescale Semiconductor
External Memory Controller (EMC)
Figure 21-33. SDRAM Bank-Staggered Auto Refresh Timing
21.4.4
User-Programmable Machines (UPMs)
The user-programmable machines (UPMs) are flexible interfaces that connect to a wide range of memory
devices. At the heart of each UPM is an internal RAM array that specifies the logical value driven on the
external memory control signals (LCSx, and LGPL[5:0]) for a given clock cycle. Each word in the RAM
array provides bits that allow a memory access to be controlled with a resolution of up to one quarter of
the external bus clock period on the chip-select lines.
shows the basic operation of each
UPM.
Figure 21-34. User-Programmable Machine Functional Block Diagram
The following events initiate a UPM cycle:
•
Any internal device requests an external memory access to an address space mapped to a
chip-select serviced by the UPM.
•
A UPM refresh timer expires and requests a transaction, such as a DRAM refresh.
1111
0000
1111
Z
ROW ADD
X
COL ADD
D0
Z
LCLK
LALE
LCS1
LCS2
LCS3
LCS4
LSDRAS
LSDCAS
LSDWE
LSDDQM
LAD[23:0]
TA
Auto
Ref
Auto
Ref
Auto
Ref
Auto
Ref
Activate
SDMR[RFCR]
Run Command
UPM Refresh
Timer Request
Array
Index
Generator
Internal / External
Memory Access Request
Exception Request
Index
Signals
Timing
Generator
Internal
Signals
Latch
Wait
Request
Logic
RAM Array
UPWAIT
WAEN Bit
Internal Controls
LGPLx
Increment
Index
(LAST = 0)
Hold
(issued in software)
LCSx
Содержание Symphony DSP56724
Страница 22: ...Symphony DSP56724 DSP56725 Multi Core Audio Processors Rev 0 1 10 Freescale Semiconductor Introduction ...
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 ...
Страница 244: ...Symphony DSP56724 DSP56725 Multi Core Audio Processors Rev 0 14 6 Freescale Semiconductor Shared Bus Arbiter ...
Страница 246: ...Symphony DSP56724 DSP56725 Multi Core Audio Processors Rev 0 15 2 Freescale Semiconductor Shared Memory Shared Memory ...