HD64F3642AHV Datasheet, PDF (134/551 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 6 ROM
6.4.2 Mode Pin Settings and ROM Space
The H8/3644F has 32 kbytes of on-chip flash memory, the H8/3643F has 24 kbytes, and the
H8/3642AF has 16 kbytes. The ROM is connected to the CPU by a 16-bit data bus. The CPU
accesses flash memory in two states for both byte-size and word-size instructions.
The flash memory is allocated to addresses H'0000 to H'7FFF in the H8/3644F, to addresses
H'0000 to H'5FFF in the H8/3643F, and to addresses H'0000 to H'3FFF in the H8/3642AF.
6.4.3 Features
The features of the flash memory are summarized below.
• Five flash memory operating modes
There are five flash memory operating modes: program mode, program-verify mode, erase
mode, erase-verify mode, and prewrite-verify mode.
• Erase block specification
Blocks to be erased in the flash memory space can be specified by setting the corresponding
register bits. The address space includes a large block area (four blocks with sizes from 4
kbytes to 8 kbytes) and a small block area (eight blocks with sizes from 128 bytes to 1 kbyte).
• Programming/erase times
The flash memory programming time is 50 µs (typ.) per byte, and the erase time is 1 s (typ.).
• Erase-program cycles
Flash memory contents can be erased and reprogrammed up to 100 times.
• On-board programming modes
There are two modes in which flash memory can be programmed, erased, and verified on-
board: boot mode and user program mode.
• Automatic bit rate adjustment
For data transfer in boot mode, the chip’s bit rate can be automatically adjusted to match the
transfer bit rate of the host (max. 9600 bps).
• PROM mode
Flash memory can be programmed and erased in PROM mode, using a general-purpose PROM
programmer, as well as in on-board programming mode. The specifications for programming,
erasing, verifying, etc., are the same as for standard HN28F101 flash memory.
Rev. 6.00 Sep 12, 2006 page 112 of 526
REJ09B0326-0600