HD64F36912GFH Renesas Electronics America, HD64F36912GFH Datasheet - Page 91

• Manufacturer Part Number: HD64F36912GFH
• Description: IC H8 MCU FLASH 8K 32-QFP
• Manufacturer: Renesas Electronics America
• Series: H8® H8/300H Tinyr

Specifications of HD64F36912GFH

• Core Processor: H8/300H
• Core Size: 16-Bit
• Speed: 12MHz
• Connectivity: I²C, SCI
• Peripherals: LVD, POR, PWM, WDT
• Number Of I /o: 18
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 75°C
• Package / Case: 32-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

3.5
3.5.1
If an interrupt is accepted after a reset and before the stack pointer (SP) is initialized, the PC and
CCR will not be saved correctly, leading to a program crash. To prevent this, all interrupt requests,
including NMI, are disabled immediately after a reset. Since the first instruction of a program is
always executed immediately after the reset state ends, make sure that this instruction initializes
the stack pointer (example: MOV.W #xx: 16, SP).
3.5.2
When word data is accessed, the least significant bit of the address is regarded as 0. Access to the
stack always takes place in word size, so the stack pointer (SP: R7) should never indicate an odd
address. Use PUSH Rn (MOV.W Rn, @–SP) or POP Rn (MOV.W @SP+, Rn) to save or restore
register values.
3.5.3
When a port mode register is rewritten to switch the functions of external interrupt pins, IRQ3,
IRQ0, and WKP5, the interrupt request flag may be set to 1.
When switching a pin function, mask the interrupt before setting the bit in the port mode register.
After accessing the port mode register, execute at least one instruction (e.g., NOP), then clear the
interrupt request flag from 1 to 0.
Figure 3.4 shows a port mode register setting and interrupt request flag clearing procedure.
Figure 3.4 Port Mode Register Setting and Interrupt Request Flag Clearing Procedure
Usage Notes
Interrupts after Reset
Notes on Stack Area Use
Notes on Rewriting Port Mode Registers
Clear interrupt request flag to 0
Set port mode register bit
Execute NOP instruction
CCR I bit
CCR I bit
1
0
Interrupts masked. (Another possibility
is to disable the relevant interrupt in
interrupt enable register 1.)
After setting the port mode register bit,
first execute at least one instruction
(e.g., NOP), then clear the interrupt
request flag to 0
Interrupt mask cleared
Rev. 3.00 Sep. 14, 2006 Page 61 of 408
Section 3 Exception Handling
REJ09B0105-0300