SH7059 Datasheet, PDF (3/1042 Pages) Renesas Technology Corp – 32-Bit RISC Microcomputer

General Precautions in the Handling of MPU/MCU Products
The following usage notes are applicable to all MPU/MCU products from Renesas. For detailed usage notes on the products covered by
this manual, refer to the relevant sections of the manual. If the descriptions under General Precautions in the Handling of MPU/MCU
Products and in the body of the manual differ from each other, the description in the body of the manual takes precedence.
1. Handling of Unused Pins
Handle unused pins in accord with the directions given under Handling of Unused Pins in the manual.
⎯ The input pins of CMOS products are generally in the high-impedance state. In operation with an unused pin in
the open-circuit state, extra electromagnetic noise is induced in the vicinity of LSI, an associated shoot-through
current flows internally, and malfunctions may occur due to the false recognition of the pin state as an input
signal. Unused pins should be handled as described under Handling of Unused Pins in the manual.
2. Processing at Power-on
The state of the product is undefined at the moment when power is supplied.
⎯ The states of internal circuits in the LSI are indeterminate and the states of register settings and pins are
undefined at the moment when power is supplied.
In a finished product where the reset signal is applied to the external reset pin, the states of pins are not
guaranteed from the moment when power is supplied until the reset process is completed.
In a similar way, the states of pins in a product that is reset by an on-chip power-on reset function are not
guaranteed from the moment when power is supplied until the power reaches the level at which resetting has
been specified.
3. Prohibition of Access to Reserved Addresses
Access to reserved addresses is prohibited.
⎯ The reserved addresses are provided for the possible future expansion of functions. Do not access these
addresses; the correct operation of LSI is not guaranteed if they are accessed.
4. Clock Signals
After applying a reset, only release the reset line after the operating clock signal has become stable. When
switching the clock signal during program execution, wait until the target clock signal has stabilized.
⎯ When the clock signal is generated with an external resonator (or from an external oscillator) during a reset,
ensure that the reset line is only released after full stabilization of the clock signal. Moreover, when switching to
a clock signal produced with an external resonator (or by an external oscillator) while program execution is in
progress, wait until the target clock signal is stable.
5. Differences between Products
Before changing from one product to another, i.e. to one with a different type number, confirm that the change will
not lead to problems.
⎯ The characteristics of MPU/MCU in the same group but having different type numbers may differ because of the
differences in internal memory capacity and layout pattern. When changing to products of different type
numbers, implement a system-evaluation test for each of the products.
Rev.3.00 Mar. 12, 2008 Page iii of xc
REJ09B0177-0300