MC68HC908GZ8MFJ Freescale Semiconductor, MC68HC908GZ8MFJ Datasheet - Page 84

• Manufacturer Part Number: MC68HC908GZ8MFJ
• Description: IC MCU 8K FLASH 8MHZ CAN 32-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908GZ8MFJ

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Connectivity: CAN, LIN, SCI, SPI
• Peripherals: LVD, POR, PWM
• Number Of I /o: 21
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 32-LQFP
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -

Computer Operating Properly (COP) Module
The COP counter is a free-running 6-bit counter preceded by a 12-bit prescaler counter. If not cleared by
software, the COP counter overflows and generates an asynchronous reset after 2
CGMXCLK cycles, depending on the state of the COP rate select bit, COPRS, in the configuration
register. With a 2
period of 53.3 ms. Writing any value to location $FFFF before an overflow occurs prevents a COP reset
by clearing the COP counter and stages 12–5 of the prescaler.
A COP reset pulls the RST pin low for 32 CGMXCLK cycles and sets the COP bit in the reset status
register (RSR).
In monitor mode, the COP is disabled if the RST pin or the IRQ1 is held at V
V
6.3 I/O Signals
The following paragraphs describe the signals shown in
6.3.1 CGMXCLK
CGMXCLK is the crystal oscillator output signal. CGMXCLK frequency is equal to the crystal frequency.
6.3.2 STOP Instruction
The STOP instruction clears the COP prescaler.
6.3.3 COPCTL Write
Writing any value to the COP control register (COPCTL) clears the COP counter and clears bits 12–5 of
the prescaler. Reading the COP control register returns the low byte of the reset vector. See
Control Register.
6.3.4 Power-On Reset
The power-on reset (POR) circuit clears the COP prescaler 4096 CGMXCLK cycles after power-up.
6.3.5 Internal Reset
An internal reset clears the COP prescaler and the COP counter.
84
TST
on the RST pin disables the COP.
Service the COP immediately after reset and before entering or after exiting
stop mode to guarantee the maximum time before the first COP counter
overflow.
Place COP clearing instructions in the main program and not in an interrupt
subroutine. Such an interrupt subroutine could keep the COP from
generating a reset even while the main program is not working properly.
13
– 2
4
CGMXCLK cycle overflow option, a 4.9152-MHz crystal gives a COP timeout
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
NOTE
NOTE
Figure
6-1.
TST
. During the break state,
18
Freescale Semiconductor
– 2
4
or 2
6.4 COP
13
– 2
4