Filter
Top Products
364
CHAPTER 16 FLASH MEMORY
16.7 Execution Status of the Automatic Algorithm
This flash memory has two hardware components for performing a Write or Erase
sequence in the automatic algorithm. These components indicate the internal
operation status of flash memory and the completion of operations to external
components. One is a Ready/Busy signal and the other is a hardware sequence flag.
■
Ready/Busy Signal (RDY/BUSYX)
The flash memory uses the Ready/Busy signal in addition to the hardware sequence flag to
indicate whether the internal automatic algorithm is running. The Ready/Busy signal is
transmitted to the flash memory interface circuit, where it can be read via the "RDY" bit of the
flash memory status register. An interrupt signal can also be generated for the CPU at the
rising edge of this Ready/Busy signal (see Section 16.1, "Outline of Flash Memory").
When the value of the "RDY" bit is "0", the flash memory is executing a write or erase operation,
where new Write and Erase commands are not accepted.
When the value of the "RDY" bit is "1", the flash memory is in read/write or erase operation wait
state.
■
Hardware Sequence Flag
For obtaining the hardware sequence flag as data, read an arbitrary address (an odd address in
byte access) from flash memory when the automatic algorithm is executed. The data contains
five validity bits which indicate the status of the automatic algorithm.
Figure 16.7-1 shows the structure of the hardware sequence flag.
Reading in units of words is inhibited.
Figure 16.7-1 Structure of the Hardware Sequence Flag
The hardware sequence flag becomes invalid in FR-CPU ROM mode. Always use FR-CPU
programming mode and write only in half-words or bytes.
15
80
7
0
SETIMR TOGGL2
DPOLL TOGGLE TLOVER
7
7
3
456
0
1
2
bit
During half-word read
Hardware sequence flag
During byte read (from odd address only)
Hardware sequence flag
(In half-word and byte access)
Undefined
UndefinedUndefined
(Undefined)