H8-3857 Datasheet, PDF (187/560 Pages) Renesas Technology Corp – 8-Bit Single-Chip Microcomputer

6. ROM
6.8.9 Writer Mode Transition Time
Commands cannot be accepted during the oscillation stabilization period or the Writer mode setup
period. A transition is made to memory read mode after the Writer mode setup time.
Table 6.20 Stipulated Transition Times to Command Wait State
Item
Standby release (oscillation stabilization time)
Writer mode setup time
V_CC hold time
Symbol
t
osc1
t_bmv
t_dwn
Min
40
10
0
Max Unit Notes
⎯ ms
⎯ ms
⎯ ms
V_CC
RES
FWE
tosc1
tbmv
Memory read
mode
command
wait state
Auto-program mode
Auto-erase mode
tdwn
Command
wait state
Don't care
Normal/abnor-
mal end
determination
Don't care
Command acceptance
Note: When not in auto-program mode or auto-erase mode, the FWE input pin should be driven low.
Figure 6.24 Oscillation Stabilization Time, Writer Mode Setup, and Power-Down Sequence
6.8.10 Notes on Memory Programming
1. When programming addresses which have previously been programmed, carry out auto-
erasing before auto-programming.
2. When performing programming using a PROM programmer on a chip that has been
programmed/erased in an on-board programming mode, auto-erasing is recommended before
carrying out auto-programming.
Notes: 1. The memory is initially in the erased state when the device is shipped by Renesas. For
other chips for which the erasure history is unknown, it is recommended that auto-
erasing be executed to check and supplement the initialization (erase) level.
2. Auto-programming should be performed once only on a particular address block.
Rev.3.00 Jul. 19, 2007 page 163 of 532
REJ09B0397-0300