HD404324FS datasheet(10/103 Pages) RENESAS

10 / 103 page

HD404054 Series/HD404094 Series

RAM-Mapped Register Area ($000–$03F):

• Interrupt Control Bits Area ($000–$003)

This area is used for interrupt control bits (figure 3). These bits can be accessed only by RAM bit

manipulation instructions (SEM/SEMD, REM/REMD, and TM/TMD). However, note that not all the

instructions can be used for each bit. Limitations on using the instructions are shown in figure 4.

• Special Function Register Area ($004–$018, $024–$034)

This area is used as mode registers and data registers for external interrupts, serial interface 1,

timer/counters, voltage comparator, and as data control registers for I/O ports. The structure is shown in

figures 2 and 5. These registers can be classified into three types: write-only (W), read-only (R), and

read/write (R/W). RAM bit manipulation instructions cannot be used for these registers.

• Register Flag Area ($020–$023)

This area is used for the WDON, and other register flags and interrupt control bits (figure 3). These bits

can be accessed only by RAM bit manipulation instructions (SEM/SEMD, REM/REMD, and

TM/TMD). However, note that not all the instructions can be used for each bit. Limitations on using

the instructions are shown in figure 4.

Memory Register (MR) Area ($040–$04F): Consisting of 16 addresses, this area (MR0–MR15) can be

accessed by register-register instructions (LAMR and XMRA). The structure is shown in figure 6.

Data Area ($090–$23F): 432 digits from $090 to $23F.

Stack Area ($3C0–$3FF): Used for saving the contents of the program counter (PC), status flag (ST), and

carry flag (CA) at subroutine call (CAL or CALL instruction) and for interrupts. This area can be used as a

16-level nesting subroutine stack in which one level requires four digits. The data to be saved and the save

conditions are shown in figure 6.

The program counter is restored by either the RTN or RTNI instruction, but the status and carry flags can

only be restored by the RTNI instruction. Any unused space in this area is used for data storage.

HD404324FS Datasheet(PDF) 10 Page - Renesas Technology Corp