Programming And Erasing Flash Memory - Renesas F-ZTAT H8 Series Hardware Manual

Section 19 Flash Memory (H8/3048F: Dual Power Supply (V
19.5

Programming and Erasing Flash Memory

The H8/3048F's on-chip flash memory is programmed and erased by software, using the CPU.
The flash memory operating modes and state transition diagram are shown in figure 19.8.
Program/erase modes comprise program mode, erase mode, program-verify mode, erase-verify
mode, and prewrite-verify mode. Transitions to these modes can be made by setting the P, E, PV,
and EV bits in the flash memory control register (FLMCR). Transition to the prewrite-verify mode
can also be made by clearing all the bits in FLMCR.
The flash memory cannot be read while being programmed or erased. The program that controls
the programming and erasing of the flash memory must be stored and executed in on-chip RAM or
in external memory. A description of each mode is given below, with recommended flowcharts
and sample programs for programming and erasing. High-reliability programming and erasing
algorithms are used, which double the programming or erase processing time for each step.
Section 19.8, Flash Memory Programming and Erasing Precautions (Dual-Power Supply), gives
further notes on programming and erasing.
V = 12 V and
PP
V E= 1
PP
P= 1
P= 0
Program mode
Note: Do not perform simultaneous setting/clearing of the P, E, PV, and EV bits.
Figure 19.8 Flash Memory Program/Erase Operating Mode State Transition Diagram
Rev. 7.00 Sep 21, 2005 page 604 of 878
REJ09B0259-0700
Normal ROM access mode
Prewrite-verify mode
E= 0
E= 1
PV= 1
Program-verify
Erase mode
= 12 V))
PP
V E= 0
PP
V off
PP
EV= 0
PV= 0
EV= 1
Erase-verify
mode
Flash memory
program/erase
operations
mode