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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 Hitachi 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
voltage.
If an input is applied to the FWE pin when the microcomputer V
satisfy the rated voltage (V
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
pin at a low level during the oscillation stabilization time (t
input to the FWE pin when oscillation is stopped or unstable.
• In the boot mode, perform FWE pin High/Low switching during reset.
In transition to the boot mode, input FWE1 and set MD
low. At this time, the FWE and MD
476
CC
= 3.0 V to 3.6 V), flash memory may be erroneously
CC
power, apply an input to the FWE pin after holding the RES
CC
to MD
2
voltage has stabilized within the rated
=20ms). Do not apply an
osc1
to MD
2
inputs must satisfy the mode programming
0
voltage does not
CC
while the RES input is
0
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