MC812A4CPVE8 Freescale Semiconductor, MC812A4CPVE8 Datasheet - Page 103

• Manufacturer Part Number: MC812A4CPVE8
• Description: IC MCU 16BIT EEPROM 4K 112-LQFP
• Manufacturer: Freescale Semiconductor
• Series: HC12r

Specifications of MC812A4CPVE8

• Core Processor: CPU12
• Core Size: 16-Bit
• Speed: 8MHz
• Connectivity: SCI, SPI
• Peripherals: POR, WDT
• Number Of I /o: 83
• Program Memory Size: 4KB (4K x 8)
• Program Memory Type: EEPROM
• Ram Size: 1K x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 112-LQFP
• Processor Series: HC812A
• Core: HC12
• Data Bus Width: 16 bit
• Data Ram Size: 1 KB
• Interface Type: SCI, SPI
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 91
• Number Of Timers: 8
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit, 8 Channel
• Controller Family/series: 68HC12
• No. Of I/o's: 91
• Eeprom Memory Size: 4KB
• Ram Memory Size: 1KB
• Cpu Speed: 8MHz
• No. Of Timers: 1
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details

10.4 Functional Description
This section provides a functional description of the MC68HC812A4.
10.4.1 Computer Operating Properly (COP)
The COP or watchdog timer is an added check that a program is running and sequencing properly. When
the COP is being used, software is responsible for keeping a free-running watchdog timer from timing out.
If the watchdog timer times out, it is an indication that the software is no longer being executed in the
intended sequence; thus, a system reset is initiated. Three control bits allow selection of seven COP
timeout periods. When COP is enabled, sometime during the selected period the program must write $55
and $AA (in this order) to the COPRST register. If the program fails to do this, the part resets. If any value
other than $55 or $AA is written, the part resets.
10.4.2 Real-Time Interrupt
There is a real-time (periodic) interrupt (RTI) available to the user. This interrupt occurs at one of seven
selected rates. An interrupt flag and an interrupt enable bit are associated with this function. The rate
select has three bits.
10.4.3 Clock Monitor
The clock monitor circuit is based on an internal resistor-capacitor (RC) time delay. If no MCU clock edges
are detected within this RC time delay, the clock monitor can generate a system reset. The clock monitor
function is enabled/disabled by the CME control bit in the COPCTL register. This timeout is based on an
RC delay so that the clock monitor can operate without any MCU clocks.
CME enables clock monitor.
Clock monitor timeouts are shown in
10.4.4 Peripheral Clock Divider Chains
Figure
Freescale Semiconductor
1 = Slow or stopped clocks (including the STOP instruction) cause a clock reset sequence.
0 = Clock monitor is disabled. Slow clocks and STOP instruction may be used.
10-4,
Figure
10-5, and
Figure 10-6
5 V ± 10%
3 V ± 10%
Table 10-1. Clock Monitor Timeouts
Supply
Table
MC68HC812A4 Data Sheet, Rev. 7
summarize the peripheral clock divider chains.
10-1.
5–100 µs
2–20 µs
Range
Functional Description
103