Chapter 17 Flash Memory
MPC5602P Microcontroller Reference Manual, Rev. 4
316
Freescale Semiconductor
In order for prefetching to occur, a number of control bits must be enabled. Specifically, the global buffer
enable (B
x
_P
y
_BFE) must be set, the prefetch limit (B
x
_P
y
_PFLM) must be non-zero and either
instruction prefetching (B
x
_P
y
_IPFE) or data prefetching (B
x
_P
y
_DPFE) enabled. Refer to
Section 17.3.6, “Registers description
for a description of these control fields.
17.2.14.1 Instruction/data prefetch triggering
Prefetch triggering may be enabled for instruction reads via the B
x
_P
y
_IPFE control field, while
prefetching for data reads is enabled via the B
x
_P
y
_DPFE control field. Additionally, the B
x
_P
y
_PFLIM
field must also be set to enable prefetching. Prefetches are never triggered by write cycles.
17.2.14.2 Per-master prefetch triggering
Prefetch triggering may be also controlled for individual bus masters. AHB accesses indicate the
requesting master via the hmaster[3:0] inputs. Refer to
Section 17.3.7.7.3, “Platform Flash Access
for details on these controls.
17.2.14.3 Buffer allocation
Allocation of the line read buffers is controlled via page buffer configuration (B
x
_P
y
_BCFG) field. This
field defines the operating organization of the four page buffers. The buffers can be organized as a “pool”
of available resources (with all four buffers in the pool) or with a fixed partition between buffers allocated
to instruction or data accesses. For the fixed partition, two configurations are supported. In one
configuration, buffers 0 and 1 are allocated for instruction fetches and buffers 2 and 3 for data accesses. In
the second configuration, buffers 0, 1, and 2 are allocated for instruction fetches and buffer 3 reserved for
data accesses.
17.2.14.4 Buffer invalidation
The page read buffers may be invalidated under hardware or software control.
Any falling edge transition of the array’s bk
n
_fl_done signal causes the page read buffers to be marked as
invalid. This input is negated by the Flash array at the beginning of all program/erase operations as well
as in certain other cases. Buffer invalidation occurs at the next AHB non-sequential access boundary, but
does not affect a burst from a page read buffer in progress.
Software may invalidate the buffers by clearing the B
x
_P
y
_BFE bit, which also disables the buffers.
Software may then re-assert the B
x
_P
y
_BFE bit to its previous state, and the buffers will have been
invalidated.
One special case needing software invalidation relates to page buffer “hits” on Flash data that was tagged
with a single-bit ECC event on the original array access. Recall that the page buffer structure includes an
status bit signaling the array access detected and corrected a single-bit ECC error. On all subsequent buffer
hits to this type of page data, a single-bit ECC event is signaled by the platform Flash controller.
Depending on the specific hardware configuration, this reporting of a single-bit ECC event may generate
an ECC alert interrupt. In order to prevent repeated ECC alert interrupts, the page buffers need to be
invalidated by software after the first notification of the single-bit ECC event.
Содержание SAFE ASSURE Qorivva MPC5601P
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Страница 4: ...MPC5602P Microcontroller Reference Manual Rev 4 4 Freescale Semiconductor ...
Страница 62: ...Chapter 2 MPC5602P Memory Map MPC5602P Microcontroller Reference Manual Rev 4 62 Freescale Semiconductor ...
Страница 104: ...Chapter 4 Clock Description MPC5602P Microcontroller Reference Manual Rev 4 104 Freescale Semiconductor ...
Страница 128: ...Chapter 6 Power Control Unit MC_PCU MPC5602P Microcontroller Reference Manual Rev 4 128 Freescale Semiconductor ...
Страница 272: ...Chapter 12 e200z0 and e200z0h Core MPC5602P Microcontroller Reference Manual Rev 4 272 Freescale Semiconductor ...
Страница 280: ...Chapter 14 Crossbar Switch XBAR MPC5602P Microcontroller Reference Manual Rev 4 280 Freescale Semiconductor ...
Страница 306: ...Chapter 16 Internal Static RAM SRAM MPC5602P Microcontroller Reference Manual Rev 4 306 Freescale Semiconductor ...
Страница 380: ...Chapter 17 Flash Memory MPC5602P Microcontroller Reference Manual Rev 4 380 Freescale Semiconductor ...
Страница 532: ...Chapter 21 LIN Controller LINFlex MPC5602P Microcontroller Reference Manual Rev 4 532 Freescale Semiconductor ...
Страница 578: ...Chapter 22 FlexCAN MPC5602P Microcontroller Reference Manual Rev 4 578 Freescale Semiconductor ...
Страница 708: ...Chapter 25 FlexPWM MPC5602P Microcontroller Reference Manual Rev 4 708 Freescale Semiconductor ...
Страница 742: ...Chapter 26 eTimer MPC5602P Microcontroller Reference Manual Rev 4 742 Freescale Semiconductor ...
Страница 760: ...Chapter 27 Functional Safety MPC5602P Microcontroller Reference Manual Rev 4 760 Freescale Semiconductor ...
Страница 782: ...Chapter 28 Fault Collection Unit FCU MPC5602P Microcontroller Reference Manual Rev 4 782 Freescale Semiconductor ...
Страница 788: ...Chapter 29 Wakeup Unit WKPU MPC5602P Microcontroller Reference Manual Rev 4 788 Freescale Semiconductor ...
Страница 798: ...Chapter 30 Periodic Interrupt Timer PIT MPC5602P Microcontroller Reference Manual Rev 4 798 Freescale Semiconductor ...
Страница 816: ...Chapter 32 Cyclic Redundancy Check CRC MPC5602P Microcontroller Reference Manual Rev 4 816 Freescale Semiconductor ...
Страница 848: ...Chapter 33 Boot Assist Module BAM MPC5602P Microcontroller Reference Manual Rev 4 848 Freescale Semiconductor ...
Страница 930: ...Chapter 36 Nexus Development Interface NDI MPC5602P Microcontroller Reference Manual Rev 4 930 Freescale Semiconductor ...