Notes On Flash Memory Programming/Erasing - Renesas H8/3067 Series User Manual

Section 18 ROM
18.9

Notes on Flash Memory Programming/Erasing

The following describes notes when using the on-board programming mode, RAM emulation
function, and PROM mode.
(1) Program/erase with the specified voltage and timing.
Applied voltages in excess of the rating can permanently damage the device.
Use a PROM writer that supports the Renesas 128kbytes flash memory on-board
microcomputer device type.
Do not set the PROM writer at the HN28F101. If the PROM writer is set to the HN28F101 by
mistake, a high level can be input to the FWE pin and the LSI can be destroyed.
(2) Notes on powering on/powering off (See figures 18.25 to 18.27.)
Input a high level to the FWE pin after verifying Vcc. Before turning off Vcc, set the FWE pin
to a low level.
When powering on and powering off the Vcc power supply, fix the FWE pin a low level and
set the flash memory to the hardware protection mode.
Be sure that the powering on and powering off timing is satisfied even when the power is
turned off and back on in the event of a power interruption, etc. If this timing is not satisfied,
microcomputer runaway, etc., may cause overprogramming or overerasing and the memory
cells may not operate normally.
(3) Notes on FWE pin High/Low switching (See figures 18.25 to 18.27.)
Input FWE in the state microcomputer operation is verified. If the microcomputer does not
satisfy the operation confirmation state, fix the FWE pin at a low level to set the protection
mode.
To prevent erroneous programming/erasing of flash memory, note the following in FWE pin
High/Low switching:
• Apply an input to the FWE pin after the Vcc voltage has stabilized within the rated
voltage.
If an input is applied to the FWE pin when the microcomputer Vcc voltage does not
satisfy the rated voltage, flash memory may be erroneously programmed or erased
because the microcomputer is in the unconfirmed state.
• Apply an input to the FWE pin when the oscillation has stabilized (after the oscillation
stabilization time).
When turning on the Vcc power, apply an input to the FWE pin after holding the RES
pin at a low level during the oscillation stabilization time (t
input to the FWE pin when oscillation is stopped or unstable.
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=20ms). Do not apply an
osc1