S9S08SG16E1MTJ Freescale Semiconductor, S9S08SG16E1MTJ Datasheet - Page 63

• Manufacturer Part Number: S9S08SG16E1MTJ
• Description: MCU 16K FLASH 20-TSSOP
• Manufacturer: Freescale Semiconductor
• Series: HCS08r

Specifications of S9S08SG16E1MTJ

• Core Processor: HCS08
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: I²C, LIN, SCI, SPI
• Peripherals: LVD. POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 20-TSSOP
• Processor Series: S08SG
• Core: HCS08
• Data Bus Width: 8 bit
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: EWS08
• Development Tools By Supplier: DEMO9S08SG32, DEMO9S08SG32AUTO, DEMO9S08SG8, DEMO9S08SG8AUTO
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

The COP counter is initialized by the first writes to the SOPT1 and SOPT2 registers after any system reset.
Subsequent writes to SOPT1 and SOPT2 have no effect on COP operation. Even if the application will use
the reset default settings of COPT, COPCLKS, and COPW bits, the user should write to the write-once
SOPT1 and SOPT2 registers during reset initialization to lock in the settings. This will prevent accidental
changes if the application program gets lost.
The write to SRS that services (clears) the COP counter should not be placed in an interrupt service routine
(ISR) because the ISR could continue to be executed periodically even if the main application program
fails.
If the bus clock source is selected, the COP counter does not increment while the MCU is in background
debug mode or while the system is in stop mode. The COP counter resumes when the MCU exits
background debug mode or stop mode.
If the 1-kHz clock source is selected, the COP counter is re-initialized to zero upon entry to either
background debug mode or stop mode and begins from zero upon exit from background debug mode or
stop mode.
5.5
Interrupts provide a way to save the current CPU status and registers, execute an interrupt service routine
(ISR), and then restore the CPU status so processing resumes where it left off before the interrupt. Other
than the software interrupt (SWI), which is a program instruction, interrupts are caused by hardware events
such as an edge on a pin interrupt or a timer-overflow event. The debug module can also generate an SWI
under certain circumstances.
If an event occurs in an enabled interrupt source, an associated read-only status flag will become set. The
CPU will not respond unless the local interrupt enable is a 1 to enable the interrupt and the I bit in the CCR
is 0 to allow interrupts. The global interrupt mask (I bit) in the CCR is initially set after reset which
prevents all maskable interrupt sources. The user program initializes the stack pointer and performs other
system setup before clearing the I bit to allow the CPU to respond to interrupts.
When the CPU receives a qualified interrupt request, it completes the current instruction before responding
to the interrupt. The interrupt sequence obeys the same cycle-by-cycle sequence as the SWI instruction and
consists of:
While the CPU is responding to the interrupt, the I bit is automatically set to avoid the possibility of another
interrupt interrupting the ISR itself (this is called nesting of interrupts). Normally, the I bit is restored to 0
when the CCR is restored from the value stacked on entry to the ISR. In rare cases, the I bit can be cleared
inside an ISR (after clearing the status flag that generated the interrupt) so that other interrupts can be
serviced without waiting for the first service routine to finish. This practice is not recommended for anyone
Freescale Semiconductor
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Saving the CPU registers on the stack
Setting the I bit in the CCR to mask further interrupts
Fetching the interrupt vector for the highest-priority interrupt that is currently pending
Filling the instruction queue with the first three bytes of program information starting from the
address fetched from the interrupt vector locations
Interrupts
MC9S08SG32 Data Sheet, Rev. 8
Chapter 5 Resets, Interrupts, and General System Control
63