HD404344R Datasheet, PDF (19/102 Pages) Renesas Technology Corp – 4-bit microcomputer has an A/D converter

HD404344R Series/HD404394 Series
RAM Map Register Area ($000 to $03F):
• Interrupt control bits area: $000 to $003
This area is made up of bits used for interrupt control as shown in figure 3. Each bit can be accessed
only by RAM bit manipulation instructions (SEM/SEMD, REM/REMD, and TM/TMD). Some bits
however, have limitations along with certain instructions as shown in figure 4.
• Special register area: $004 to $01F, $024 to $03F
This area is made up of mode registers and data registers, such as for external interrupt, serial interface,
timers, A/D converter, and data control for the I/O ports. Its configurations are shown in figures 2 and 5.
These registers are categorized as write-only, read-only, and write/read. They can not be accessed by
RAM bit manipulation instructions.
• Register flag area: $020 to $023
This area is used for the WDON flag and other interrupt control flags. Its configuration is shown in
figure 3. Each bit can be accessed only by the SEM/SEMD, REM/REMD, and TM/TMD instructions.
Some bits however, have limitations along with certain instructions as shown in figure 4.
Data Area ($040 to $0FF): Sixteen of the 176 digits in this area, from $040 to $04F, are memory registers.
These registers can be accessed by the LAMR and XMRA instructions. Its configuration is shown in figure
6.
Stack Area ($3C0 to $3FF): This area is used to hold the program counter (PC), the status flag (ST), and
the carry flag (CA) for subroutine calls (CAL and CALL instructions) and interrupts. Since four digits are
used for each level, this area can be used for stacking up to 16 subroutines. The stacking order of saved
data and the storing of bits are shown in figure 6. The program counter is recovered by the RTN and RTNI
instructions. The status and carry flags are recovered only by the RTNI instruction.
Any area not used in the stack area is available for data storage.
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