M32C8A Datasheet, PDF (352/372 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M32C/80 Series

M32C/8A Group
24. Usage Notes
24.3.4.2 Stop Mode
• The MCU cannot enter stop mode if a low-level (“L”) signal is applied to the NMI pin. Apply an “H” signal
to enter stop mode.
• To exit stop mode by reset, apply an “L” signal to RESET pin until a main clock oscillation stabilizes.
• If using the NMI interrupt to exit stop mode, use the following procedure to set the CM10 bit in the CM1
register to 1 (all clocks stopped).
(Technical update: TN-16C-127A/EA)
(1) Exit stop mode using the NMI interrupt.
(2) Generate a dummy interrupt.
(3) Set the CM10 bit to 1 (all clocks stopped).
e.g., int #63
bset CM1
; dummy interrupt
; all clocks stopped
/*dummy interrupt routine*/
dummy
reit
• When entering stop mode, the instructions following CM10 = 1 instruction are stored into the instruction
queue, and the program stops. When stop mode is exited, the instruction lined in the queue is executed
before the exit interrupt routine is handled. Insert a jmp.b instruction as follows after the instruction to set
the CM10 bit is set to 1.
(Technical update: TN-16C-124A/EA)
fset I
bset 0, cm1
jmp.b LABEL_001
LABEL_001:
nop
nop
nop
nop
mov.b #0, prcr
.
.
.
; I flag is set to 1
; all clocks stopped (stop mode)
; jmp.b instruction executed (no instruction between jmp.b and LABEL.)
; nop(1)
; nop(2)
; nop(3)
; nop(4)
; protection set
Rev.1.00 Jul 15, 2007 Page 335 of 352
REJ09B0385-0100