4283 Group
✕ Power-on reset
11
Note on product shipped in blank
Under the following condition, the system reset occurs by the
built-in the power-on reset circuit of this product;
As for the product shipped in blank, Renesas does not perform
the writing test to user ROM area after the assembly process
though the QzROM writing test is performed enough before
the assembly process. Therefore, a writing error of approx.
0.1 % may occur.
Moreover, please note the contact of cables and foreign bodies
on a socket, etc. because a writing environment may cause
some writing errors.
-
when the supply voltage (VDD) rises from 0 V to 2.2 V, within
1 ms.
Also, note that system reset does not occur under the
following conditions;
-
-
when the supply voltage (VDD) rises from the voltage higher
than 0V, or
when it takes more than 1 ms for the supply voltage (VDD)
to rise from 0 V to 2.2 V.
12
QzROM
(1) Be careful not to apply overvoltage to MCU. The contents
of QzROM may be overwritten because of overvoltage.
Take care especially at turning on the power.
✕ Voltage drop detection circuit
The voltage drop detection circuit detection voltage of this
product is set up lower than the minimum value of the supply
voltage of the recommended operating conditions.
A battery exchange of an application product is explained as
an example.
The supply voltage falls below to the recommended operating
voltage while CPU keeps active. Then, an unexpected
oscillation-stop, which does not happen by POF instruction
occurs before the supply voltage falls below to the detection
voltage. In this time, even if the supply voltage re-goes up to
the recommended operating voltage, since reset does not
occur, MCU may not operate correctly.
(2) As for the product shipped in blank, Renesas does not per-
form the writing test to user ROM area after the assembly
process though the QzROM writing test is performed
enough before the assembly process. Therefore, a writing
error of approx.0.1 % may occur. Moreover, please note
the contact of cables and foreign bodies on a socket, etc.
because a writing environment may cause some writing er-
rors.
13
Notes On ROM Code Protect
(QzROM product shipped after writing)
Please confirm the oscillator you use and the frequency of
system clock, and test the operation of your system sufficiently.
As for the QzROM product shipped after writing, the ROM
code protect is specified according to the ROM option setup
data in the mask file which is submitted at ordering.
The ROM option setup data in the mask file is “0016” for pro-
tect enabled or “FF16” for protect disabled.
Note that the mask file which has nothing at the ROM option
data or has the data other than “0016” and “FF16” can not be
accepted.
VDD
Recommended operatng
condition min.value
Oscillation is stopped
incorrectly.
VDET
Even if the voltage re-goes up to
the recommended operating voltage,
MCU may not operate correctly.
→ Normal operation
VDD
Recommended
operatng condition
min.value
VDET
Reset
Fig. 30 VDD and VDET
✕ Note on Power Source Voltage
When the power source voltage value of a microcomputer is
less than the value which is indicated as the recommended
operating conditions, the microcomputer does not operate
normally and may perform unstable operation.
In a system where the power source voltage drops slowly when
the power source voltage drops or the power supply is turned
off, reset a microcomputer when the supply voltage is less
than the recommended operating conditions and design a
system not to cause errors to the system by this unstable
operation.
Rev.1.01 Mar 20, 2006 page 24 of 62
REJ03B0109-0101
RENESAS [ RENESAS TECHNOLOGY CORP ]
