![Freescale Semiconductor PXR4030 Скачать руководство пользователя страница 1312](http://html1.mh-extra.com/html/freescale-semiconductor/pxr4030/pxr4030_reference-manual_23306601312.webp)
External Bus Interface (EBI)
30-50
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
•
Copy the code that is doing the register writes (plus a return branch) to internal SRAM
•
Branch to internal SRAM to run this code, ending with a branch back to external flash
30.5.2
Running with SDR (Single Data Rate) Burst Memories
This includes FLASH and SRAM memories with a compatible burst interface. D_BDIP is required only
for some SDR memories.
shows a block diagram of an MCU connected to a 32-bit SDR burst
memory.
Figure 30-38. MCU Connected to SDR Burst Memory
Refer to
for an example of the timing of a typical Burst Read operation to an SDR burst
memory. Refer to
for an example of the timing of a typical Single Write operation to SDR
memory.
30.5.3
Running with Asynchronous Memories
The EBI also supports asynchronous memories. In this case, the D_CLKOUT, D_TS, and D_BDIP pins
are not used by the memory and bursting is not supported. However, the EBI still drives these outputs, and
always drives and latches all signals at posedge D_CLKOUT (i.e., there is no “asynchronous mode” for
the EBI). The data timing is controlled by setting the SCY bits in the appropriate Option Register to the
proper number of wait states to work with the access time of the asynchronous memory, just as done for a
synchronous memory.
30.5.3.1
Example Wait State Calculation
This example applies to any chip-select memory, synchronous or asynchronous.
As an example, say we have a memory with 50ns access time, and we are running the external bus
@ 66 MHz (D_CLKOUT period: 15.2ns). Assume the input data spec for the MCU is 4ns.
number of wait states = (access time) / (D_CLKOUT period) + (0 or 1) (depending on setup time)
D_CLKOUT
CS0
D_TS
D_ADD[9:30]
D_BDIP
D_OE
MCU
CK
CE
ADV
BAA*
WE**
A[0:21]
D[0:31]
OE
SDR Burstable
Flash or SRAM
* May or may not be connected, depending on the memory used.
Flash memories typically use one WE signal as shown, RAMs use 2 or 4 (16-bit or 32-bit).
**
D_ADD_DAT[0:31]
D_WE0
Содержание PXR4030
Страница 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Страница 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Страница 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Страница 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Страница 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 158: ...Power Management Controller PMC 5 26 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 182: ...Frequency Modulated Phase Locked Loop FMPLL 6 24 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 278: ...System Integration Unit SIU 7 96 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 280: ...System Information Module PXR40 Microcontroller Reference Manual Rev 1 8 2 Freescale Semiconductor...
Страница 300: ...Boot Assist Module BAM 9 20 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 346: ...Interrupts and Interrupt Controller INTC 10 46 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 352: ...General Purpose Static RAM SRAM 11 6 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 432: ...Core e200z7 Overview PXR40 Microcontroller Reference Manual Rev 1 13 44 Freescale Semiconductor...
Страница 460: ...Peripheral Bridge PBRIDGE 15 16 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 478: ...Memory Protection Unit MPU 16 18 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 496: ...Error Correction Status Module ECSM 17 18 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 524: ...Periodic Interrupt Timer PIT_RTI 20 12 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 740: ...FlexRay Communication Controller FLEXRAY 22 156 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 928: ...Deserial Serial Peripheral Interface DSPI 25 68 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 982: ...Enhanced Serial Communication Interface eSCI 26 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1114: ...Enhanced Queued Analog to Digital Converter EQADC 27 132 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Страница 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1262: ...Enhanced Time Processing Unit eTPU2 29 94 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1399: ...Nexus Development Interface NDI Freescale Semiconductor 31 83 PXR40 Microcontroller Reference Manual Rev 1...
Страница 1400: ...Nexus Development Interface NDI 31 84 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...