HD64F2638F20J Renesas Electronics America, HD64F2638F20J Datasheet - Page 328
Manufacturer Part Number
IC H8S MCU FLASH 256K 128-QFP
Renesas Electronics America
Specifications of HD64F2638F20J
CAN, SCI, SmartCard
Motor Control PWM, POR, PWM, WDT
Number Of I /o
Program Memory Size
256KB (256K x 8)
Program Memory Type
16K x 8
Voltage - Supply (vcc/vdd)
4.5 V ~ 5.5 V
A/D 12x10b; D/A 2x8b
-40°C ~ 85°C
Package / Case
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Bonase Electronics (HK) Co., Limited
Section 3 Processing States
After the RES pin has gone low and the reset state has been entered, reset exception handling
starts when RES goes high again. When reset exception handling starts the CPU fetches a start
address (vector) from the exception vector table and starts program execution from that address.
All interrupts, including NMI, are disabled during reset exception handling and after it ends.
Traces are enabled only in interrupt control modes 2 and 3. Trace mode is entered when the T bit
of EXR is set to 1. When trace mode is established, trace exception handling starts at the end of
At the end of a trace exception-handling sequence, the T bit of EXR is cleared to 0 and trace mode
is cleared. Interrupt masks are not affected.
The T bit saved on the stack retains its value of 1, and when the RTE instruction is executed to
return from the trace exception-handling routine, trace mode is entered again. Trace exception-
handling is not executed at the end of the RTE instruction.
Trace mode is not entered in interrupt control modes 0 and 1, regardless of the state of the T bit.
When interrupt or trap-instruction exception handling begins, the CPU references the stack pointer
(ER7) and pushes the program counter and other control registers onto the stack. Next, the CPU
alters the settings of the interrupt mask bits in the control registers. Then the CPU fetches a start
address (vector) from the exception vector table and execution branches to that address.
Figure 3.3 shows the stack after exception handling ends, for the case of interrupt mode 1 in
(1) Conflict between Interrupt Generation and Disabling
When an interrupt enable bit is cleared to 0 to disable interrupts, the disabling becomes effective
after execution of the instruction.
When an interrupt enable bit is cleared to 0 by an instruction such as BCLR or MOV, and if an
interrupt is generated during execution of the instruction, the interrupt concerned will still be
Rev. 4.00 Feb 24, 2006 page 312 of 322
Reset Exception Handling
Interrupt Exception Handling and Trap Instruction Exception Handling