UPD78F0411GA-GAM-AX Datasheet, PDF (505/564 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 23 OPTION BYTE
23.1 Functions of Option Bytes
The flash memory at 0080H to 0084H of the 78K0/LC3 is an option byte area. When power is turned on or when
the device is restarted from the reset status, the device automatically references the option bytes and sets specified
functions. When using the product, be sure to set the following functions by using the option bytes.
When the boot swap operation is used during self-programming, 0080H to 0084H are switched to 1080H to 1084H.
Therefore, set values that are the same as those of 0080H to 0084H to 1080H to 1084H in advance.
Caution Be sure to set 00H to 0082H and 0083H (0082H/1082H and 0083H/1083H when the boot swap
function is used).
(1) 0080H/1080H
{ Internal low-speed oscillator operation
• Can be stopped by software
• Cannot be stopped
{ Watchdog timer interval time setting
{ Watchdog timer counter operation
• Enabled counter operation
• Disabled counter operation
{ Watchdog timer window open period setting
Caution Set a value that is the same as that of 0080H to 1080H because 0080H and 1080H are
switched during the boot swap operation.
(2) 0081H/1081H
{ Selecting POC mode
• During 2.7 V/1.59 V POC mode operation (POCMODE = 1)
The device is in the reset state upon power application and until the supply voltage reaches 2.7 V (TYP.). It
is released from the reset state when the voltage exceeds 2.7 V (TYP.). After that, POC is not detected at
2.7 V but is detected at 1.59 V (TYP.).
If the supply voltage rises to 1.8 V after power application at a pace slower than 0.5 V/ms (MIN.), use of the
2.7 V/1.59 V POC mode is recommended.
• During 1.59 V POC mode operation (POCMODE = 0)
The device is in the reset state upon power application and until the supply voltage reaches 1.59 V (TYP.).
It is released from the reset state when the voltage exceeds 1.59 V (TYP.). After that, POC is detected at
1.59 V (TYP.), in the same manner as on power application.
Caution POCMODE can only be written by using a dedicated flash memory programmer. It cannot be
set during self-programming or boot swap operation during self-programming (at this time,
1.59 V POC mode (default) is set). However, because the value of 1081H is copied to 0081H
during the boot swap operation, it is recommended to set a value that is the same as that of
0081H to 1081H when the boot swap function is used.
User’s Manual U18698EJ1V0UD
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