HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 598

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

18.7 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 18-14.
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 18.10, Flash Memory Programming and Erasing Precautions, gives further notes on
programming and erasing.
Figure 18-14 Flash Memory Program/Erase Operating Mode State Transition Diagram
Note: Do not perform simultaneous setting/clearing of the P, E, PV, and EV bits.
Program mode
P= 1
V
V
P= 0
PP
PP
= 12 V and
E= 1
E= 1
Erase mode
Normal ROM access mode
Prewrite-verify mode
E= 0
PV= 1
Program-verify
589
mode
V
V
PV= 0
PP
PP
E= 0
off
EV= 1
EV= 0
Erase-verify
mode
Flash memory
program/erase
operations