HD64F3642AHV Datasheet, PDF (128/551 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 6 ROM
6.3.1 Writing and Verifying
An efficient, high-speed, high-reliability method is available for writing and verifying the PROM
data. This method achieves high speed without voltage stress on the device and without lowering
the reliability of written data. Data in unused address areas has a value of H'FF. The basic flow of
this high-speed, high-reliability programming method is shown in figure 6.3.
Start
Set write/verify mode
V_CC = 6.0 V ±0.25 V, V_PP = 12.5 V ±0.3 V
Address = 0
n=0
Yes
No
n < 25
n+1 →n
Write time t_PW = 0.2 ms ±5%
NG
Verify
OK
Write time t_OPW = 3n ms
No
Last address?
Yes
Set read mode
V_CC = 5.0 V ±0.5 V, V_PP = V_CC
Address + 1 → address
Error
NG
Read all
addresses?
Yes
End
Figure 6.3 High-Speed, High-Reliability Programming Flow Chart
Rev. 6.00 Sep 12, 2006 page 106 of 526
REJ09B0326-0600