MC9S12XD256MAL Datasheet, PDF (97/1348 Pages) Freescale Semiconductor, Inc – Freescale’s Scalable Controller Area Network

Chapter 2 Clocks and Reset Generator (S12CRGV6)
2.3.2.12 CRG COP Timer Arm/Reset Register (ARMCOP)
This register is used to restart the COP time-out period.
R
W
Reset
7
0
Bit 7
0
6
0
Bit 6
0
5
0
Bit 5
0
4
0
Bit 4
0
3
0
Bit 3
0
2
0
Bit 2
0
1
0
Bit 1
0
0
0
Bit 0
0
Figure 2-15. ARMCOP Register Diagram
Read: Always reads 0x_00
Write: Anytime
When the COP is disabled (CR[2:0] = “000”) writing to this register has no effect.
When the COP is enabled by setting CR[2:0] nonzero, the following applies:
Writing any value other than 0x_55 or 0x_AA causes a COP reset. To restart the COP time-out
period you must write 0x_55 followed by a write of 0x_AA. Other instructions may be executed
between these writes but the sequence (0x_55, 0x_AA) must be completed prior to COP end of
time-out period to avoid a COP reset. Sequences of 0x_55 writes or sequences of 0x_AA writes
are allowed. When the WCOP bit is set, 0x_55 and 0x_AA writes must be done in the last 25% of
the selected time-out period; writing any value in the first 75% of the selected period will cause a
COP reset.
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
97