h8s-2138 Renesas Electronics Corporation., h8s-2138 Datasheet - Page 90

• Manufacturer Part Number: h8s-2138
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2100 Series
• Manufacturer: Renesas Electronics Corporation.

Section 2 CPU
Free area
SP (ER7)
Stack area
Figure 2.9 Stack
2.4.3
Control Registers
The control registers are the 24-bit program counter (PC), 8-bit extended control register (EXR),
and 8-bit condition-code register (CCR).
(1) Program Counter (PC)
This 24-bit counter indicates the address of the next instruction the CPU will execute. The length
of all CPU instructions is 2 bytes (one word), so the least significant PC bit is ignored. (When an
instruction is fetched, the least significant PC bit is regarded as 0.)
(2) Extended Control Register (EXR)
An 8-bit register. In the H8S/2138 Group and H8S/2134 Group, this register does not affect
operation.
Bit 7—Trace Bit (T): This bit is reserved. In the H8S/2138 Group and H8S/2134 Group, this bit
does not affect operation.
Bits 6 to 3—Reserved: These bits are reserved. They are always read as 1.
Bits 2 to 0—Interrupt Mask Bits (I2 to I0): These bits are reserved. In the H8S/2138 Group and
H8S/2134 Group, these bits do not affect operation.
Rev. 4.00 Jun 06, 2006 page 36 of 1004
REJ09B0301-0400