SH7046 Datasheet, PDF (527/611 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7046 Series

Section 18 Flash Memory (F-ZTAT Version)
18.13 Notes on Flash Memory Programming and Erasing
Precautions concerning the use of on-board programming mode, the RAM emulation function, and
programmer mode are summarized below.
Use the specified voltages and timing for programming and erasing: Appling excessive
voltage beyond the specification can permanently damage the device. Use an EPROM
programmer that supports the Renesas' microcomputer device having on-chip 256-kbyte flash
memory. Use only the specified socket adapter, otherwise a serious damage may occur.
Powering on and off (see figures 18.11 to 18.13): Do not apply a low level to the FWP pin until
V_CC has been stabilized. Also, drive the FWP pin high before turning off V_CC. If V_CC is to be
applied or disconnected, fix the FWP pin level at V_CC and place the flash memory in the hardware
protection state in advance.
Conditions for this power-on and power-off timing should also be applied in the event of a power
failure and subsequent recovery.
FWP application/disconnection (see figures 18.11 to 18.13): If V_CC is on or off while low level
is applied to FWP pin, a voltage surge from low level on the RESET pin may cause unintentional
programming or erasing of flash memory. Applying voltage to FWP should be carried out while
MCU operation is in a stable condition. If MCU operation is not stable, fix the FWP pin high and
set the protection state. The following points must be observed concerning FWP application and
disconnection to prevent unintentional programming or erasing of flash memory:
• Apply voltage to FWP while the V_CC voltage is stable enough to satisfy the specification
voltage range.
• In boot mode, apply voltage to FWP or disconnect it during a reset.
• Prior to applying voltage while FWP pin is in low level in boot mode, ensure that the RESET
pin level is surely kept low despite the applying voltage is rising to V_CC. Note that in a case
where ICs for reset are used, the voltage level of RESET pin can transiently exceed 1/2 V_CC
while V_CC is rising.
• In user program mode, FWP can be switched between high and low level regardless of the
reset state. FWP input can also be switched during execution of a program in flash memory.
• Apply voltage to FWP while programs are not running away.
• Disconnect FWP only when the SWE, ESU, PSU, EV, PV, P, and E bits in FLMCR1 are
cleared. Make sure that the SWE, ESU, PSU, EV, PV, P, and E bits are not set by mistake
when applying voltage to FWP pin or disconnecting.
Do not apply a constant low level to the FWP pin: If a program runs away while low level is
applied to FWP pin, incorrect programming or erasing may occur. Apply a low level to the FWP
Rev. 4.00 Dec 05, 2005 page 483 of 564
REJ09B0270-0400