HD64F3028F25 Datasheet, PDF (58/925 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series

2.5.2 Memory Data Formats
Figure 2.8 shows the data formats on memory. The H8/300H CPU can access word data and
longword data on memory, but word or longword data must begin at an even address. If an attempt
is made to access word or longword data at an odd address, no address error occurs but the least
significant bit of the address is regarded as 0, so the access starts at the preceding address. This
also applies to instruction fetches.
Data Type
Address
Data Format
1-bit data
Address L
7
0
76543210
Byte data
Address L
MSB
LSB
Word data
Address 2M
MSB
Address 2M + 1
LSB
Address 2N
MSB
Longword data Address 2N + 1
Address 2N + 2
Address 2N + 3
LSB
Figure 2.8 Memory Data Formats
When ER7 (SP) is used as an address register to access the stack, the operand size should be word
size or longword size.
Rev. 2.00, 09/03, page 26 of 890