HD404639R Datasheet, PDF (18/135 Pages) Renesas Technology Corp – 4-Bit Single-Chip Microcomputer

HD404639R Series
Item
Carry flag
Abbr.
(CA)
Accumulator
(A)
B register
(B)
W register
(W)
X/SPX register
(X/SPX)
Y/SPY register
(Y/SPY)
Serial data register
(SRL, SRU)
RAM
RAM enable flag
(RAME)
Port mode register C bit 2 (PMRC2)
System clock select
register 1 bit 3
(SSR13)
Status After
Status After
Cancellation of Stop Cancellation of
Mode by STOPC
Stop Mode by
Input
MCU Reset
Status After all
Other Types of
Reset
Pre-stop-mode values are not guaranteed;
values must be initialized by program
Pre-stop-mode
values are not
guaranteed; values
must be initialized by
program
Pre-stop-mode values are retained
1
0
0
Pre-stop-mode values 0
0
are retained
Interrupts
The MCU has 11 interrupt sources: five external signals (INT₀ , INT₁, INT₂, INT₃, INT₄), four
timer/counters (timers A, B, C, and D), and two serial interfaces (serial interface 1, serial interface 2).
An interrupt request flag (IF), interrupt mask (IM), and vector address are provided for each interrupt
source, and an interrupt enable flag (IE) controls the entire interrupt process.
Some vector addresses are shared by two different interrupts. They are timer B and INT₂, timer C and
INT₃, timer D and INT₄, and serial interface 1 and serial interface 2. So the type of request that has
occurred must be checked at the beginning of interrupt processing.
Interrupt Control Bits and Interrupt Processing: Locations $000 to $003 and $022 to $023 in RAM are
reserved for the interrupt control bits which can be accessed by RAM bit manipulation instructions.
The interrupt request flag (IF) cannot be set by software. MCU reset initializes the interrupt enable flag
(IE) and the IF to 0 and the interrupt mask (IM) to 1.
A block diagram of the interrupt control circuit is shown in figure 9, interrupt priorities and vector
addresses are listed in table 2, and interrupt processing conditions for the 11 interrupt sources are listed in
table 3.
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