Explanation Of Flash Memory Operation - Fujitsu FR60 Hardware Manual

17.3

Explanation of Flash Memory Operation

This section describes flash memory operation.
■ Flash Memory Access Modes
The following two types of access mode are available for the FR-CPU:
• ROM mode:
One word (32 bits) can be read but not written in a single cycle.
• Programming mode:
Access to data with a length defined in words (32 bits) is prohibited but writing data with a length
defined in half-words (16 bits) is enabled.
■ FR-CPU ROM Mode (32 Bits, Read only)
In this mode, the flash memory serves as FR-CPU internal ROM. This mode enables to read one word (32
bits) in one cycle but does not enable to write to flash memory or to start the automatic algorithm.
• Mode specification
• When specifying this mode, set the "WE" bit of the FLCR register to "0".
• This mode is always set after a reset releases at CPU run time.
• This mode can be set only when the CPU is running.
• Detailed operation
In this mode, one word (32 bits) can be read from the flash memory area in one cycle.
• Restrictions
• Address assignment and endians in this mode differ from those for writing with the ROM writer.
• In this mode, commands and data cannot be written to flash memory together.
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