NEC 78K0R/KE3 User Manual page 851

Function Details of
Function
Flash Security settings After the security setting for the batch erase is set, erasure cannot be performed for
memory
Flash memory
programming by
self-
programming
Flash shield
window function
On-chip Connecting QB-
debug MINI2 to
function 78K0R/KE3
BCD Addition
correction
circuit
Subtraction
Instruction PREFIX
set instruction
APPENDIX B LIST OF CAUTIONS
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.
The self-programming function cannot be used when the CPU operates with the
subsystem clock.
In the self-programming mode, call the self-programming start library (FlashStart).
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.
The self-programming function is disabled in the low consumption current mode. For
details of the low consumption current mode, see CHAPTER 21 REGULATOR.
Disable DMA operation (DENn = 0) during the execution of self programming library
functions.
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.
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.
occurring when the on-chip debug function is used.
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.
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.
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.
Set the ES register value with MOV ES, A, etc., before executing the PREFIX
instruction.
User's Manual U17854EJ9V0UD
Cautions
NEC Electronics is not liable for problems
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