Toggle Bit Flag (Dq6) - Fujitsu MB90480 Series Hardware Manual

F2mc-16lx 16-bit microcontroller

Table of Contents

23.5.2 Toggle Bit Flag (DQ6)

Like the data polling flag (DQ7), the toggle bit flag (DQ6) is a flag mainly used to

indicate whether the automatic algorithm is being executed or has ended. In the case

of the toggle bit flag, a toggle bit function is used for that purpose.

State transitions of the toggle bit flag (DQ6)

❍ State transitions in normal operation

❍ State transitions in operation error mode

Write/chip sector erase operations

In the case of repeated read accesses when the automatic write algorithm and the chip sector

erase algorithm are being executed, the flash memory toggles between output of 1 and 0 in

toggle mode for each read operation independent of addressing. When repeated read accesses

are performed when the automatic write algorithm and chip/sector erase algorithm have ended,

the flash memory stops with the toggle operation of bit6, and instead outputs bit6 (DATA: 6) of

the read value for the specified address.

Sector erase suspend

If read access is performed when a sector erase operation is suspended, the flash memory

outputs "1" when the specified address belongs to the sector being erased. In other cases, bit6

(DATA: 6) of the read value for the specified address will be output.

If, in write operations, the sector to be written is rewrite-protected, toggle operation is

performed for about 2 μs before the operation ends without any data being rewritten.

If, in erase operation, all selected sectors are rewrite-protected, toggle operation is

performed for about 100 μs before the device returns to the read/reset state without any data

being rewritten.

CHAPTER 23 2M/3M BIT FLASH MEMORY

Sector erase

Sector erase

erase suspend

(sector being

Sector erased

Suspend mode

Sector not being