HD64F2149 Datasheet, PDF (108/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

2.9.5 External Address Space Access Timing
The external address space is accessed with an 8-bit or 16-bit data bus width in a two-state or
three-state bus cycle. In three-state access, wait states can be inserted. For further details, refer to
section 6, Bus Controller.
2.10 Usage Note
2.10.1 TAS Instruction
Only register ER0, ER1, ER4, or ER5 should be used when using the TAS instruction. The TAS
instruction is not generated by the Hitachi H8S and H8/300 series C/C++ compilers. If the TAS
instruction is used as a user-defined intrinsic function, ensure that only register ER0, ER1, ER4, or
ER5 is used.
2.10.2 STM/LDM Instruction
ER7 is not used as the register that can be saved (STM)/restored (LDM) when using STM/LDM
instruction, because ER7 is the stack pointer. Two, three, or four registers can be saved/restored
by one STM/LDM instruction. The following ranges can be specified in the register list.
Two registers: ER0—ER1, ER2—ER3, or ER4—ER5
Three registers: ER0—ER2 or ER4—ER6
Four registers: ER0—ER3
The STM/LDM instruction including ER7 is not generated by the Hitachi H8S and H8/300 series
C/C++compilers.
74