MC9S12XD256MAL Datasheet, PDF (94/1348 Pages) Freescale Semiconductor, Inc – Freescale’s Scalable Controller Area Network

Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.9 CRG COP Control Register (COPCTL)
This register controls the COP (computer operating properly) watchdog.
7
6
5
4
R
0
0
WCOP
RSBCK
W
WRTMASK
Reset¹
0
0
0
3
2
0
CR2
0
1. Refer to Device User Guide (Section: CRG) for reset values of WCOP, CR2, CR1, and CR0.
= Unimplemented or Reserved
1
CR1
0
CR0
Figure 2-12. CRG COP Control Register (COPCTL)
Read: Anytime
Write:
1. RSBCK: Anytime in special modes; write to “1” but not to “0” in all other modes
2. WCOP, CR2, CR1, CR0:
— Anytime in special modes
— Write once in all other modes
Writing CR[2:0] to “000” has no effect, but counts for the “write once” condition.
Writing WCOP to “0” has no effect, but counts for the “write once” condition.
The COP time-out period is restarted if one these two conditions is true:
1. Writing a nonzero value to CR[2:0] (anytime in special modes, once in all other modes) with
WRTMASK = 0.
or
2. Changing RSBCK bit from “0” to “1”.
Table 2-9. COPCTL Field Descriptions
Field
7
WCOP
6
RSBCK
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, 0x_55 can be written as often as desired. Once 0x_AA is written after the 0x_55, the time-out logic
restarts and the user must wait until the next window before writing to ARMCOP. Table 2-10 shows the 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.
MC9S12XDP512 Data Sheet, Rev. 2.21
94
Freescale Semiconductor