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Section 20 Power-Down State
20.4.6
Cautions on Clearing the Software Standby Mode of F-ZTAT Version
(1) Operation phenomena
When using operating mode 5, 6, or 7* (on-chip flash memory enabled), the first read of on-
chip flash memory after exiting software standby mode may not be carried out correctly.
Software standby mode is exited by means of an external interrupt (via the NMI, IRQ
or IRQ
pin), the RES pin, or the STBY pin. In the case of an external interrupt via the NMI,
2
IRQ
, IRQ
, or IRQ
0
1
vector corresponding to the respective exception handling interrupt source. This vector may
not be read correctly, resulting in program runaway.
Note: * Mode 5: expanded 16-Mbyte mode with on-chip ROM enabled
Mode 6: single-chip normal mode
Mode 7: single-chip advanced mode
(2) Exemplary procedures to avoid program runaway
This operation phenomenon can be avoided by writing or amending program code in
accordance with the following procedures.
(a) When using mode 5 or mode 7, assign addresses in the 64-kbyte space from H'00000 to
H'0FFFF as the vector addresses for the external interrupts that clear software standby
mode.
(b) When using mode 6, change the mode to mode 7 in the program, and use change (a) above.
Note that it is necessary to change vector address assignments and to extend addresses as
follows.
• Addresses H'DFFF and below (on-chip ROM area): H'xxxx → H'0xxxx
• Addresses H'E000 to H'E0FF (internal I/O registers-1): H'yyyy → H'Eyyyy
• Addresses H'EF20 and above (on-chip RAM area and internal I/O registers-2): H'zzzz
→ H'Fzzzz
(Where x, y and z are any hexadecimal numbers)
With the production lots prior to the week code "9K1" of the HD64F3067 and
HD64F3067R, avoid program runaway according to the procedures designated above.
Meanwhile, as for the production lots of the week code "9K1" and after, the special
constraint according to of the aforementioned Section (2) is not applicable.
Rev. 4.00 Jan 26, 2006 page 688 of 938
REJ09B0276-0400
pin, the first read after exiting software standby mode is a read of the
2
, IRQ
,
0
1
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