h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 753

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

4. Do not apply a constant high level to the FWE pin.
5. Use the recommended algorithm when programming and erasing flash memory.
6. Do not set or clear the SWE bit during execution of a program in flash memory.
7. Do not use interrupts while flash memory is being programmed or erased.
8. Do not perform additional programming. Erase the memory before reprogramming.
9. Before programming, check that the chip is correctly mounted in the PROM
Apply a high level to the FWE pin only when programming or erasing flash memory. A
system configuration in which a high level is constantly applied to the FWE pin should be
avoided. Also, while a high level is applied to the FWE pin, the watchdog timer should be
activated to prevent overprogramming or overerasing due to program runaway, etc.
The recommended algorithm enables programming and erasing to be carried out without
subjecting the device to voltage stress or sacrificing program data reliability. When setting the
P or E bit in FLMCR1, the watchdog timer should be set beforehand as a precaution against
program runaway, etc.
Do not set or clear the SWE bit during execution of a program in flash memory. Wait for at
least 100 µs after clearing the SWE bit before executing a program or reading data in flash
memory. When the SWE bit is set, data in flash memory can be rewritten, but when SWE = 1,
flash memory can only be read in program-verify or erase-verify mode. Access flash memory
only for verify operations (verification during programming/erasing). Do not clear the SWE bit
during programming, erasing, or verifying.
Similarly, when using the RAM emulation function while a high level is being input to the
FWE pin, the SWE bit must be cleared before executing a program or reading data in flash
memory. However, the RAM area overlapping flash memory space can be read and written to
regardless of whether the SWE bit is set or cleared.
All interrupt requests, including NMI, should be disabled during FWE application to give
priority to program/erase operations.
In on-board programming, perform only one programming operation on a 128-byte
programming unit block. In programmer mode, also, perform only one programming operation
on a 128-byte programming unit block. Further programming must only be executed after this
programming unit block has been erased.
programmer.
Overcurrent damage to the device can result if the index marks on the PROM programmer
socket, socket adapter, and chip are not correctly aligned.
Rev. 5.00 Sep 22, 2005 page 727 of 1136
REJ09B0257-0500
Section 20 ROM