Toshiba H1 SERIES TLCS-900 - Manual (Page 23)

TMP92CM22
2007-02-16 92CM22-21
(3) Runaway provision with SFR protection register
(Purpose)
Provision in runaway of program by noise mixing.
Write operation to specified SFR is prohibited so that provision program in
runaway prevents that is in the state which is fetch impossibility by stopping of
clock, memory control register (Memory controller) is changed.
And error handling in runaway becomes easy by INTP0 interruption.
Specified SFR list
1. Memory controller
B0CSL/H, B1CSL/H, B2CSL/H, B3CSL/H, BEXCSL/H,
MSAR0, MSAR1, MSAR2, MSAR3,
MAMR0, MAMR1, MAMR2, MAMR3, and PMEMCR
2. Clock gear (EMCCR1, EMCCR2 write enable)
SYSCR0, SYSCR1, SYSCR2, and EMCCR0
(Operation explanation)
Execute and release of protection (write operation to specified SFR) becomes
possible by setting up a double key to EMCCR1 and EMCCR2 registers.
(Double key)
1st-KEY: Succession writes in 5AH at EMCCR1 and A5H at EMCCR2.
2nd-KEY: Succession writes in A5H at EMCCR1 and 5AH at EMCCR2.
A state of protection can be confirmed by reading EMCCR0<PROTECT>.
By reset, protection becomes OFF.
And INTP0 interruption occurs when write operation to specified SFR was
executed with protection on state.