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Preliminary User’s Manual U17566EE1V2UM00
Chapter 6 Flash Memory
The µPD70F3420, µPD70F3421, µPD70F3422, µPD70F3422, µPD70F3423,
µPD70F3424, µPD70F3425, µPD70F3426 and µPD70F3427 microcontrollers
are equipped with internal flash memory. The flash memory is attached to the
V850 Fetch Bus VFB interface of the V850E CPU core. It is used for program
code and storage of constant data.
When fetching an instruction, 4 bytes of the flash memory can be accessed in
1 clock.
The flash memory can be written mounted on the target board (on-board
write), by connecting a dedicated flash programmer to the target system.
Flash memory is commonly used in the following development environments
and applications:
• For altering software after solder-mounting of the microcontroller on the
target system.
• For differentiating software in small-scale production of various models.
• For data adjustment when starting mass production.
6.1 Overview
Features summary
• Internal VFB flash memory:
– µPD70F3427, µPD70F3426, µPD70F3425: 1 MB
– µPD70F3424, µPD70F3423: 512 KB
– µPD70F3422: 384 KB
– µPD70F3421: 256 KB
– µPD70F3420: 128 KB
• µPD70F3427, µPD70F3426, µPD70F3425, µPD70F3424 operation speed:
up to 50.4 MHz by 2-way interleaved access
– 4-byte/1 CPU clock cycle access for consecutive instruction fetches
– 4-byte/5 CPU clock cycles access for random instruction and data fetches
• µPD70F3423 operation speed:
up to 25.2 MHz by 2-way interleaved access
– 4-byte/1 CPU clock cycle access for consecutive instruction fetches
– 4-byte/3 CPU clock cycles access for random instruction and data fetches
• µPD70F3422, µPD70F3421, µPD70F3420 operation speed:
up to 25.2 MHz with non-interleaved access
• All-blocks batch erase or single block erase
• Erase/write with single power supply
• Communication with dedicated flash programmer via various serial
interfaces
• On-board and off-board programming
• Flash memory programming by self-programming
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