M38867E8AHP MITSUBISHI [Mitsubishi Electric Semiconductor], M38867E8AHP Datasheet - Page 81

• Manufacturer Part Number: M38867E8AHP
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER??
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

(3) Flash memory mode 3 (CPU reprogramming
mode)
The M38869FFAHP/GP has the CPU reprogramming mode where
a built-in flash memory is handled by the central processing unit
(CPU).
In CPU reprogramming mode, the flash memory is handled by
writing and reading to/from the flash memory control register (see
Figure 79) and the flash command register (see Figure 80).
The CNV
gramming mode. It is necessary to apply the power-supply voltage
of V
Functional Outline (CPU reprogramming mode)
Figure 79 shows the flash memory control register bit configura-
tion. Figure 80 shows the flash command register bit
configuration.
Bit 0 of the flash memory control register is the CPU reprogram-
ming mode select bit. When this bit is set to “1” and V
applied to the CNVss/V
selected. Whether the CPU reprogramming mode is realized or
not is judged by reading the CPU reprogramming mode monitor
flag (bit 2 of the flash memory control register).
Bit 1 is a busy flag which becomes “1” during erase and program
execution.
Fig. 79 Flash memory control register bit configuration
PP
H from the external to this pin.
SS
pin is used as the V
7
6
0
Note: Bit 0 can be reprogrammed only when 0 V is applied to the CNVSS/VPP pin.
5
PP
4
pin, the CPU reprogramming mode is
3
0
PP
2
power supply pin in CPU repro-
1
0
Flash memory control regsiter
(FCON : address 0FFE16)
CPU reprogramming mode select bit (Note)
Erase/Program busy flag
CPU reprogramming mode monitor flag
Fix this bit to “0.”
Erase/Program area select bits
Fix this bit to “0.”
Not used (returns "0" when read)
0 : CPU reprogramming mode is invalid. (Normal operation mode)
1 : When applying 0 V or VPPL to CNVSS/VPP pin, CPU reprogramming mode is
0 : Erase and program are completed or not have been executed.
1 : Erase/program is being executed.
0 : CPU reprogramming mode is invalid.
1 : CPU reprogramming mode is valid.
0 0 : Addresses 100016 to FFFF16 (total 60 Kbytes)
0 1 : Addresses 100016 to 7FFF16 (total 28 Kbytes)
1 0 : Addresses 800016 to FFFF16 (total 32 Kbytes)
1 1 : Not available
invalid. When applying VPPH to CNVSS/VPP pin, CPU reprogramming mode is valid.
PP
H is
Whether these operations have been completed or not is judged
by checking this flag after each command of erase and the pro-
gram is executed.
Bits 4, 5 of the flash memory control register are the erase/pro-
gram area select bits. These bits specify an area where erase and
program is operated. When the erase command is executed after
an area is specified by these bits, only the specified area is
erased. Only for the specified area, programming is enabled; for
the other areas, programming is disabled.
When CPU reprogramming mode is valid, the area where is not
specified by the erase/program area select bits cannot be read
out.
Transfer CPU reprogramming mode control program to internal
RAM before entering the CPU reprogramming mode, and then ex-
ecute this program on internal RAM.
If an interrupt occurs while this program is being executed, the
flash memory area is accessed, but normally operation cannot be
performed because the flash memory area cannot be read out.
During CPU reprogramming mode control program execution, ex-
ecute the processing such as interrupt disabled, etc.
Figure 81 shows the CPU mode register bit configuration in the
CPU reprogramming mode. Set bits 1 and 0 to “00” (single-chip
mode) in the CPU reprogramming mode.
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
MITSUBISHI MICROCOMPUTERS
3886 Group
81