Datasheet

Chapter 11 S12XE Clocks and Reset Generator (S12XECRGV1)
MC9S12XE-Family Reference Manual Rev. 1.25
Freescale Semiconductor 485
Write: Only in special modes
11.3.2.12 S12XECRG COP Timer Arm/Reset Register (ARMCOP)
This register is used to restart the COP time-out period.
Read: Always reads $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 $55 or $AA causes a COP reset. To restart the COP time-out period
you must write $55 followed by a write of $AA. Other instructions may be executed between these
writes but the sequence ($55, $AA) must be completed prior to COP end of time-out period to
avoid a COP reset. Sequences of $55 writes or sequences of $AA writes are allowed. When the
WCOP bit is set, $55 and $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.
Module Base + 0x000B
76543210
R00000000
W Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Reset 0 0 0 00000
Figure 11-14. S12XECRG ARMCOP Register Diagram