HD404629R Datasheet, PDF (13/157 Pages) Renesas Technology Corp – AS Microcomputer Incorporating a DTMF Generator Circuit

HD404629R Series
RAM Memory Map
The MCU contains a 1,876-digit × 4-bit RAM area consisting of a memory register area, an LCD data area,
a data area, and a stack area. In addition, an interrupt control bits area, special register area, and register
flag area are mapped onto the same RAM memory space as a RAM-mapped register area outside the above
areas. The RAM memory map is shown in figure 2 and described below.
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–$01F, $024–$03F)
This area is used as mode registers and data registers for external interrupts, serial interface,
timer/counters, LCD, A/D converter, 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). The SEM, SEMD, REM, and REMD instructions can be used for the LCD control
register (LCR: $01B), but RAM bit manipulation instructions cannot be used for other registers.
• Register Flag Area ($020–$023)
• This area is used for the DTON, 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.
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