Renesas Hitachi H8S/2191, Hardware Manual

Page: 245 / 1065

Rev. 2.0, 11/00, page 218 of 1037
(5) Use the Recommended Algorithm when Programming and Erasing Flash Memory
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 Pn or En bit in FLMCR1 and FLMCR2, the watchdog timer should be set beforehand as a
precaution against program runaway, etc.
(6) Do Not Set or Clear the SWE Bit During Program Execution in Flash Memory
Clear 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 flash memory should
only be accessed for verify operations (verification during programming/erasing).
(7) Do Not Use Interrupts while Flash Memory is Being Programmed or Erased
All interrupt requests, including NMI, should be disabled during FWE application to give
priority to program/erase operations.
(8) Do Not Perform Additional Programming. Erase the Memory before Reprogramming.
In on-board programming, perform only one programming operation on a 32-byte
programming unit block. In programmer mode, too, perform only one programming
operation on a 128-byte programming unit block. Programming should be carried out with
the entire programming unit block erased.
(9) Before Programming, Check that the Chip is Correctly Mounted in the PROM 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.
(10)Do Not Touch the Socket Adapter or Chip During Programming.
Touching either of these can cause contact faults and write errors.