m37905 Renesas Electronics Corporation., m37905 Datasheet - Page 421

• Manufacturer Part Number: m37905
• Description: Mitsubishi 16-bit Single-chip Microcomputer 7700 Family / 7900 Series
• Manufacturer: Renesas Electronics Corporation.

1. In the flash memory CPU reprogramming mode, an opcode cannot be fetched for the internal flash memory.
2. In order to prevent any interrupt occurrence during the flash memory CPU reprogramming mode, before selecting
3. Commands and data must be read from and written into even-numbered addresses in the user ROM area, 16 bits
4. Be sure not to execute the STP instruction in the CPU reprogramming mode.
5. In order to reset the internal flash memory control circuit by using the flash memory reset bit (bit 3 at address 9E
6. Addresses FF90
FLASH MEMORY VERSION
[Precautions for flash memory CPU reprogramming mode]
[Precautions for flash memory CPU reprogramming mode]
19-18
Accordingly, be sure to transfer the reprogramming control software to an area other than the internal flash memory
area, and then execute the software in this area. (See Figure 19.2.2.)
Also, take consideration for instruction description (such as specified addresses, addressing modes) in the repro-
gramming control software since this software is to be executed in an area other than the internal flash memory
area.
this mode, be sure to set the interrupt disable flag (I) to “1” or set the interrupt priority level to “000
disabled). Also, we recommend to connect pins P4OUT
Even in the flash memory CPU reprogramming mode, periodically writing to the watchdog timer is required.
Also, an interrupt, hardware reset, or software reset, generated in the CPU reprogramming mode, makes program
runaway. If a program runaway has occurred, be sure to push the microcomputer into the power-on reset state.
at a time.
be sure to confirm the RY/BY status bit (bit 0 at address 9E
write “0” to the flash memory reset bit.
use this area.
16
to FF9F
16
(the user ROM area) are reserved for serial and parallel programmers. Be sure not to
7905 Group User’s Manual Rev.1.0
CUT
and P6OUT
16
) becomes “1” after writing of “1” to this bit; and then,
CUT
with V
CC
via resistors, respectively.
2
” (interrupts
16
),