UPD78F9234MC-5A4-A Datasheet, PDF (408/419 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

APPENDIX D LIST OF CAUTIONS
Function
Details of
Function
Cautions
(17/20)
Page
Option byte
Use of RESET
pin as an input-
only port pin
(P34)
Flash
memory
PG-FP5 GUI
Software setting
value example
Security settings
Self
programming
function
Be aware of the following when re-erasing/-writing (by on-board programming
using a dedicated flash memory programmer) an already-written device which
has been set as “The RESET pin is used as an input-only port pin (P34)” by
the option byte function.
Before supplying power to the target system, connect a dedicated flash
memory programmer and turn its power on. If the power is supplied to the
target system beforehand, the flash memory programming mode cannot be
switched to.
p.271
The above values are recommended values. Depending on the usage
environment these values may change, so set them after having performed
sufficient evaluations.
p.278
After the security setting of 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.281
Self programming processing must be included in the program before
performing self programming.
p.282
No instructions can be executed while a self programming command is being
executed. Therefore, clear and restart the watchdog timer counter in advance
so that the watchdog timer does not overflow during self programming. Refer
to Table 19-10 for the time taken for the execution of self programming.
p.285
Interrupts that occur during self programming can be acknowledged after self
programming mode ends. To avoid this operation, disable interrupt servicing
(by setting MK0 and MK1 to FFH, and executing the DI instruction) before a
mode is shifted from the normal mode to the self programming mode with a
specific sequence.
p.285
RAM is not used while a self programming command is being executed.
p.285
If the supply voltage drops or the reset signal is input while the flash memory p.285
is being written or erased, writing/erasing is not guaranteed.
The value of the blank data set during block erasure is FFH.
p.285
Set the CPU clock beforehand so that it is 1 MHz or higher during self
programming.
p.285
Execute self programming after executing the NOP and HALT instructions
immediately after executing a specific sequence to set self programming
mode. At this time, the HALT instruction is automatically released after 10 μs
(MAX.) + 2 CPU clocks (fCPU).
p.285
If the clock of the oscillator or an external clock is selected as the system
clock, execute the NOP and HALT instructions immediately after executing a
specific sequence to set self programming mode, wait for 8 μs after releasing
the HALT status, and then execute self programming.
p.285
Check FPRERR using a 1-bit memory manipulation instruction.
p.285
The state of the pins in self programming mode is the same as that in HALT
mode.
p.285
406
User’s Manual U17446EJ5V0UD