Fujitsu FR81S Manual Do Utilizador
CHAPTER 46: WORKFLASH MEMORY
2. Features
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : WORKFLASH MEMORY
FUJITSU SEMICONDUCTOR CONFIDENTIAL
4
2. Features
This section explains features of the WorkFlash memory.
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Usable capacity:
MB91F52x : 64K bytes (8K bytes × 8 sectors)
For ECC code storage, there are 6 bits of built-in flash memory for every 4 bytes.
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High-speed operation:
read on a word-by -word basis (32 bit) is possible by 80 MHz × 2 cycle.
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Write from external: Possible from ROM writer
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Operation mode:
(1) CPU-ROM mode
(CPU/DMA accesses flash memory. Only read)
Only data access is enabled. Instruction fetch is not enabled.
(2) CPU programming mode
(CPU accesses flash memory. Read/Write/Erase)
(3) Flash memory mode
(Access flash memory from the external is enabled.)
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Security function
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Operations after instruction fetch from external and write/erase except for chip erase at security on
are inhibited to avoid reading out flash memory data by an outsider.
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The use of on-chip debugger (OCD) enables read from external by using OCD, even if security is
on after password authentication.
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Error correction code (ECC) function
There is an error correction code (ECC) function that corrects errors of up to one bit in each word. (A
function for detecting 2-bit errors is not provided.) Errors are automatically corrected during read.
Furthermore, ECC codes are automatically added when writing to the flash memory. Because there is no
read cycle penalty due to error correction, no consideration needs to be given to error correction penalties
during software development.
*: Automatic Algorithm=Embedded Algorithm
MB91520 Series
MN705-00010-1v0-E
1975