MC9S12NE64CPVE Datasheet, PDF (154/554 Pages) Freescale Semiconductor, Inc – MC9S12NE64 Device Overview

Chapter 4 Clocks and Reset Generator (CRGV4)
4.3.2.9 CRG COP Control Register (COPCTL)
This register controls the COP (computer operating properly) watchdog.
7
6
5
4
R
0
0
WCOP
RSBCK
W
Reset
0
0
0
0
= Unimplemented or Reserved
3
2
1
0
0
CR2
CR1
CR0
0
0
0
0
Read: anytime
Figure 4-12. CRG COP Control Register (COPCTL)
Write: WCOP, CR2, CR1, CR0: once in user mode, anytime in special mode
Write: RSBCK: once
Table 4-8. COPCTL Field Descriptions
Field
7
WCOP
6
RSBCK
2:0
CR[2:0]
Description
Window COP Mode Bit — When set, a write to the ARMCOP register must occur in the last 25% of the selected
period. A write during the first 75% of the selected period will reset the part. As long as all writes occur during
this window, 0x0055 can be written as often as desired. As soon as 0x00AA is written after the 0x0055, the
time-out logic restarts and the user must wait until the next window before writing to ARMCOP. Table 4-9 shows
the exact duration of this window for the seven available COP rates.
0 Normal COP operation
1 Window COP operation
COP and RTI Stop in Active BDM Mode Bit
0 Allows the COP and RTI to keep running in active BDM mode.
1 Stops the COP and RTI counters whenever the part is in active BDM mode.
COP Watchdog Timer Rate Select — These bits select the COP time-out rate (see Table 4-9). The COP
time-out period is OSCCLK period divided by CR[2:0] value. Writing a nonzero value to CR[2:0] enables the COP
counter and starts the time-out period. A COP counter time-out causes a system reset. This can be avoided by
periodically (before time-out) reinitializing the COP counter via the ARMCOP register.
Table 4-9. COP Watchdog Rates¹
CR2
CR1
CR0
OSCCLK
Cycles to Time Out
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
COP disabled
2¹⁴
2¹⁶
2¹⁸
2²⁰
2²²
2²³
2²⁴
1 _{OSCCLK cycles are referenced from the previous COP time-out reset}
(writing 0x0055/0x00AA to the ARMCOP register)
MC9S12NE64 Data Sheet, Rev. 1.1
154
Freescale Semiconductor