HD64F3437TFI16V Renesas Electronics America, HD64F3437TFI16V Datasheet - Page 492

• Manufacturer Part Number: HD64F3437TFI16V
• Description: MCU FLASH 60K 100-TQFP
• Manufacturer: Renesas Electronics America

Specifications of HD64F3437TFI16V

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

PVOK:
NGEND:
20.4.4
To erase the flash memory, follow the erasing algorithm shown in figure 20.9. This erasing
algorithm can erase data without subjecting the device to voltage stress or impairing the reliability
of programmed data.
To erase flash memory, before starting to erase, first place all memory data in all blocks to be
erased in the programmed state (program all memory data to H'00). If all memory data is not in the
programmed state, follow the sequence described later to program the memory data to zero. Select
the flash memory areas to be erased with erase block registers 1 and 2 (EBR1 and EBR2). Next set
the E bit in FLMCR, selecting erase mode. The erase time is the time during which the E bit is set.
To prevent overerasing, use a software timer to divide the time for a single erase, and ensure that
the total time does not exceed 30 seconds. For the time for a single erase, refer to section 20.4.6,
Erase Flowchart and Sample Programs. Overerasing, due to program runaway for example, can
give memory cells a negative threshold voltage and cause them to operate incorrectly. Before
selecting erase mode, set up the watchdog timer so as to prevent overerasing.
20.4.5
In erase-verify mode, after data has been erased, it is read to check that it has been erased
correctly. After the erase time has elapsed, exit erase mode (clear the E bit to 0) and select erase-
verify mode (set the EV bit to 1). Before reading data in erase-verify mode, write H'FF dummy
data to the address to be read. This dummy write applies an erase-verify voltage to the memory
cells at the latched address. If the flash memory is read in this state, the data at the latched address
will be read. After the dummy write, wait 2 s or more before reading. When performing the
initial dummy write, wait 4 s or more after selecting erase-verify mode. If the read data has been
successfully erased, perform an erase-verify (dummy write, wait 2 s or more, then read) for the
next address. If the read data has not been erased, select erase mode again and repeat the same
erase and erase-verify sequence through the last address, until all memory data has been erased to
1. Do not repeat the erase and erase-verify sequence more than 602 times, however.
460
Erase Mode
Erase-Verify Mode
CMP.B
BEQ
ADD.W
BRA
BCLR
MOV.B
MOV.B
One byte programmed
Programming error
#H'06,
NGEND
R5,
PRGMS
#2,
#H'00,
R6L,
R6L
R5
@FLMCR:8
R6L
@EBR*:8
; Program-verify executed 6 times?
; If program-verify executed 6 times, branch to NGEND
; Programming time
; Program again
;
;
;
Clear EBR
Clear PV bit
*
2