H8SLASH3021 datasheet(516/712 Pages) RENESAS

516 / 712 page

15. ROM

Rev.2.00 Mar. 22, 2007 Page 492 of 684

REJ09B0352-0200

15.11

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 programmer that supports Renasas Technology microcomputer device type F-

ZTAT256V3 with 256-kbyte on-chip flash memory.

Do not set the PROM programmer at the HN28F101. If the PROM programmer 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 15.17 to 15.19.)

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 15.17 to 15.19.)

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 V

CC voltage has stabilized within the rated

voltage.

If an input is applied to the FWE pin when the microcomputer V

CC voltage does not

satisfy the rated voltage (V

CC = 3.0 V to 3.6 V), 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 V

CC power, apply an input to the FWE pin after holding the RES

pin at a low level during the oscillation stabilization time (t

osc1=20ms). Do not apply an

input to the FWE pin when oscillation is stopped or unstable.

• In the boot mode, perform FWE pin High/Low switching during reset.

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