Section 6 ROM
Rev. 7.00 Mar 10, 2005 page 154 of 652
REJ09B0042-0700
6.5 Flash Memory Overview
6.5.1 Features
The features of the 32-Kbyte or 16-Kbyte flash memory built into the flash memory versions are
summarized below.
• Programming/erase methods
 The flash memory is programmed 128 bytes at a time. Erase is performed in single-block
units. On the HD64F38024, HD64F38024R, and HD64F38124 the flash memory is
configured as follows: 1 Kbyte × 4 blocks, 28 Kbytes × 1 block. On the HD64F38122 the
flash memory is configured as follows: 1 Kbyte × 4 blocks, 12 Kbytes × 1 block. To erase
the entire flash memory, each block must be erased in turn.
• Reprogramming capability
 The HD64F38024R, HD64F38124, and HD64F38122 can be reprogrammed up to 1,000
times and the HD64F38024 up to 100 times.
• On-board programming
 On-board programming/erasing can be done in boot mode, in which the boot program built
into the chip is started to erase or program of the entire flash memory. In normal user
program mode, individual blocks can be erased or programmed.
• Programmer mode
 Flash memory can be programmed/erased in programmer mode using a PROM
programmer, as well as in on-board programming mode.
• Automatic bit rate adjustment
 For data transfer in boot mode, this LSI's bit rate can be automatically adjusted to match
the transfer bit rate of the host.
• Programming/erasing protection
 Sets software protection against flash memory programming/erasing.
• Power-down mode
 The power supply circuit is partly halted in the subactive mode and can be read in the
power-down mode.
Note: The system clock oscillator must be used when programming or erasing the flash memory
of the HD64F38124 and HD64F38122.
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