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Bus Operation
MCF5253 Reference Manual, Rev. 1
Freescale Semiconductor
8-15
Figure 8-16. Master Reset Timing
During the master reset period, the data bus is being tri-stated, the address bus is driven to any value, and
all other bus signals are driven to their negated state. Once RSTI negates, the bus stays in this state until
the core begins the first bus cycle for reset exception processing. A master reset causes any bus cycle
(including DRAM refresh cycle) to terminate. In addition, master reset initializes registers appropriately
for a reset exception.
If at power-on reset, the MCF5253 is configured to boot from external memory connected to CS0. Then
CS0 is configured to address the external boot ROM / Flash. The configuration for CS0 at this time is
hard-wired inside the MCF5253.
Configuration is summarized in
.
8.7.1
Software Watchdog Reset
The software watchdog reset is performed anytime the executing software does not provide the correct
write sequence with the enable-control bit set. This reset helps recovery from runaway software or
nonterminated bus cycles. During the software watchdog reset period all signals are driven either to a high
impedance state or a negated state as appropriate.
Table 8-9. Power-On Reset Configuration for CS0
Port Size
16 Bits
Cycle type
Internal termination, 15 wait cycles
Burst inhibit asserted for both read and write cycles
VDD
RSTI
CRIN
D[31:16]
SDRAS
,
SDCAS
CS, OE
>16
CLKIN CYCLES
SDWE
,
BCLKE
A[23:1], RW
Содержание MCF5253
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Страница 46: ...MCF5253 Introduction MCF5253 Reference Manual Rev 1 1 14 Freescale Semiconductor...
Страница 62: ...Signal Description MCF5253 Reference Manual Rev 1 2 16 Freescale Semiconductor...
Страница 98: ...Instruction Cache MCF5253 Reference Manual Rev 1 5 10 Freescale Semiconductor...
Страница 104: ...Static RAM SRAM MCF5253 Reference Manual Rev 1 6 6 Freescale Semiconductor...
Страница 128: ...Synchronous DRAM Controller Module MCF5253 Reference Manual Rev 1 7 24 Freescale Semiconductor...
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Страница 176: ...System Integration Module SIM MCF5253 Reference Manual Rev 1 9 32 Freescale Semiconductor...
Страница 198: ...Analog to Digital Converter ADC MCF5253 Reference Manual Rev 1 12 6 Freescale Semiconductor...
Страница 246: ...DMA Controller MCF5253 Reference Manual Rev 1 14 18 Freescale Semiconductor...
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Страница 370: ...Boot ROM MCF5253 Reference Manual Rev 1 19 8 Freescale Semiconductor...