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APPENDIX B LIST OF CAUTIONS
User’s Manual U17854EJ9V0UD
851
(27/33)
Chapter
Cl
assi
fi
cati
on
Function
Details of
Function
Cautions
Page
Security settings
After the security setting for the batch erase is set, erasure cannot be performed for
the device.
In addition, even if a write command is executed, data different from that which has
already been written to the flash memory cannot be written, because the erase
command is disabled.
p.670
Hard
The self-programming function cannot be used when the CPU operates with the
subsystem clock.
p.673
In the self-programming mode, call the self-programming start library (FlashStart).
p.673
To prohibit an interrupt during self-programming, in the same way as in the normal
operation mode, execute the self-programming library in the state where the IE flag
is cleared (0) by the DI instruction.
To enable an interrupt, clear (0) the interrupt mask flag to accept in the state where
the IE flag is set (1) by the EI instruction, and then execute the self-programming
library.
p.673
The self-programming function is disabled in the low consumption current mode. For
details of the low consumption current mode, see CHAPTER 21 REGULATOR.
p.673
Flash memory
programming by
self-
programming
Disable DMA operation (DENn = 0) during the execution of self programming library
functions.
p.673
Chapter
2
3
Soft
Flash
memory
Flash shield
window function
If the rewrite-prohibited area of the boot cluster 0 overlaps with the flash shield
window range, prohibition to rewrite the boot cluster 0 takes priority.
p.677
The 78K0R/KE3 has an on-chip debug function, which is provided for development
and evaluation. Do not use the on-chip debug function in products designated for
mass production, because the guaranteed number of rewritable times of the flash
memory may be exceeded when this function is used, and product reliability
therefore cannot be guaranteed.
NEC Electronics is not liable for problems
occurring when the on-chip debug function is used.
p.678
Chapter
2
4
Hard
On-chip
debug
function
Connecting QB-
MINI2 to
78K0R/KE3
When communicating in 2-line mode, a clock with a frequency of half that of the CPU
clock frequency is output from the TOOL1 pin. A resistor or ferrite bead can be used
as a countermeasure against fluctuation of the power supply caused by that clock.
p.678
Addition
The value read from the BCDADJ register varies depending on the value of the A
register when it is read and those of the CY and AC flags. Therefore, execute the
instruction <3> after the instruction <2> instead of executing any other instructions.
To perform BCD correction in the interrupt enabled state, saving and restoring the A
register is required within the interrupt function.
PSW (CY flag and AC flag) is
restored by the RETI instruction.
p.682
Chapter
2
5
Soft
BCD
correction
circuit
Subtraction
The value read from the BCDADJ register varies depending on the value of the A
register when it is read and those of the CY and AC flags. Therefore, execute the
instruction <3> after the instruction <2> instead of executing any other instructions.
To perform BCD correction in the interrupt enabled state, saving and restoring the A
register is required within the interrupt function.
PSW (CY flag and AC flag) is
restored by the RETI instruction.
p.683
Chapter
2
6
Soft
Instruction
set
PREFIX
instruction
Set the ES register value with MOV ES, A, etc., before executing the PREFIX
instruction.
p.687