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373
CHAPTER 21 ELECTRICAL SPECIFICATIONS
User
’
s Manual U15017EJ2V0UD
Flash Memory Programming Characteristics (
μ
PD78F4976A only)
(T
A
= 10 to 40
°
C, V
DD
= AV
DD
= 4.5 to 5.5 V, V
SS
= AV
SS
= 0 V, V
PP
= 9.7 to 10.3 V) (2/2)
(2) Write erase characteristics
Parameter
Symbol
Conditions
MIN.
TYP.
MAX.
Unit
V
PP
power supply
voltage
V
PP2
During flash memory programming
9.7
10.0
10.3
V
V
DD
power
supply current
I
DD
When V
PP
= V
PP2
, f
XX
= 12.5 MHz
40
mA
V
PP
power
supply current
I
PP
When V
PP
= V
PP2
100
mA
Step erase time
T
er
Note 1
0.2
s
Overall erase
time per area
T
era
When step erase time = 0.2 s
Note 2
20
s/area
Write-back time
T
wb
Note 3
50
ms
Number of write-
backs per write-back
command
C
wb
When write-back time = 50 ms
Note 4
60
times/
write-
back
com-
mand
Number of erase/
write-backs
C
erwb
16
times
Step write time
T
wr
Note 5
50
μ
s
Overall write time
per word
T
wrw
When step write time = 50
μ
s (1 word = 1 byte)
Note 6
50
500
μ
s/
word
Number of rewrites
per area
C
erwr
1 erase + 1 write after erase = 1 rewrite
Note 7
20
Note 8
times/
area
Notes 1.
The recommend setting value for the step erase time is 0.2 s.
2.
The rewrite time before erasure and the erase verify time (write-back time) is not included.
3.
The recommended setting value for the write-back time is 50 ms.
4.
Write-back is executed once by the issuance of the write-back command. Therefore, the retry times
must be the maximum value minus the number of commands issued.
5.
Recommended value of the step write time is 50
μ
s.
6.
The actual write time per word is 100
μ
s longer. The internal verify time during or after a write is not
included.
7.
When a product is first written after shipment,
“
erase
→
write
”
and
“
write only
”
are both taken as one
rewrite.
Example P: Write, E: Erase
Shipped product
→
P
→
E
→
P
→
E
→
P: 3 rewrites
Shipped product
→
E
→
P
→
E
→
P
→
E
→
P: 3 rewrites
8.
The operation when rewriting is performed more than 20 times cannot be guaranteed.
Remarks 1.
The range of the operating clock during flash memory programming is the same as the range during
normal operation.
2.
When using the PG-FP3 or FL-PR3, the time parameters that need to be downloaded from the
parameter files for write/erase are automatically set. Unless otherwise directed, do not change the
set values.