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Boot Assist Module (BAM)
MPC5644A Microcontroller Reference Manual, Rev. 6
Freescale Semiconductor
627
The watchdog timeout periods, when the watchdogs are controlled by RCHW, are shown in
.
Table 21-4. RCHW field description
Field
Description
bits 0–3
Reserved
These bit values are ignored when the halfword is read. Write to 0 for future compatibility.
SWT
Watchdog timer enable
This bit determines if the software watchdog timer is enabled after passing control to the user
application code.
0 Disable software watchdog timer
1 Software watchdog timer maintains its default state out of reset, i.e. enabled. The timeout period is
programmed to be 261600 system clocks.
WTE
Device core Watchdog timer enable
This bit determines if the core software watchdog timer is enabled.after passing control to the user
application code.
0 Disable core software watchdog timer
1 Software watchdog timer maintains its default state out of reset, i.e. enabled. The timeout period is
programmed to be 2.5*2
17
system clocks.
PS0
Port size
Defines the width of the data bus connected to the memory on CS0. After system reset, CS0 is
changed to a 16-bit port by the BAM, which fetches the RCHW from either 16- or 32-bit external
memories. Then the BAM reconfigures the EBI as a 16-bit bus or a 32-bit bus, according to the
settings of this bit.
0 32-bit CS0 port size
1 16-bit CS0 port size
Note:
Used in EBI boot mode only. Do not set the port to 32-bits if the device only has a 16-bit data
bus.
VLE
VLE Code Indicator
This bit is used to configure the MMU entries 1-3 coded as either Power Architecture instructions or
as Freescale VLE instructions.
0 User code executes as Power Architecture code
1 User code executes as Freescale VLE code
BOOTID
Boot identifier
This field serves two functions. First, it is used to indicate which block in flash memory contains the
boot program. Second, it identifies whether the flash memory is programmed or invalid. The value of
a valid boot identifier is 0x5A.
Table 21-5. Watchdog timeouts
Crystal frequency (MHz)
Core WD timeout
1
(ms)
1
327,680 system clocks
SWT timeout
2
(ms)
2
261,600 system clocks
8
40.1
32.7
12
27.3
21.8
16
20.5
16.35
20
16.4
13.08
40
8.2
6.54
Summary of Contents for MPC5644A
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Page 52: ...Introduction MPC5644A Microcontroller Reference Manual Rev 6 52 Freescale Semiconductor...
Page 56: ...Memory Map MPC5644A Microcontroller Reference Manual Rev 6 56 Freescale Semiconductor...
Page 1228: ...Decimation Filter MPC5644A Microcontroller Reference Manual Rev 6 1228 Freescale Semiconductor...
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