MC9S12P32MFT Freescale Semiconductor, MC9S12P32MFT Datasheet - Page 293

• Manufacturer Part Number: MC9S12P32MFT
• Description: 16-bit Microcontrollers - MCU 16 BIT 32K FLASH
• Manufacturer: Freescale Semiconductor

Specifications of MC9S12P32MFT

• Rohs: yes
• Core: S12
• Processor Series: MC9S12P
• Data Bus Width: 16 bit
• Maximum Clock Frequency: 32 MHz
• Program Memory Size: 32 KB
• Data Ram Size: 4 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3.13 V to 5.5 V
• Operating Temperature Range: - 40 C to + 125 C
• Package / Case: QFN-48
• Mounting Style: SMD/SMT

8.4.3.1
The MSCAN protects the user from accidentally violating the CAN protocol through programming errors.
The protection logic implements the following features:
8.4.3.2
Figure 8-43
The clock source bit (CLKSRC) in the CANCTL1 register (8.3.2.2/8-259) defines whether the internal
CANCLK is connected to the output of a crystal oscillator (oscillator clock) or to the bus clock.
The clock source has to be chosen such that the tight oscillator tolerance requirements (up to 0.4%) of the
CAN protocol are met. Additionally, for high CAN bus rates (1 Mbps), a 45% to 55% duty cycle of the
clock is required.
If the bus clock is generated from a PLL, it is recommended to select the oscillator clock rather than the
bus clock due to jitter considerations, especially at the faster CAN bus rates.
Freescale Semiconductor
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The receive and transmit error counters cannot be written or otherwise manipulated.
All registers which control the configuration of the MSCAN cannot be modified while the MSCAN
is on-line. The MSCAN has to be in Initialization Mode. The corresponding INITRQ/INITAK
handshake bits in the CANCTL0/CANCTL1 registers (see
Register 0
— MSCAN control 1 register (CANCTL1)
— MSCAN bus timing registers 0 and 1 (CANBTR0, CANBTR1)
— MSCAN identifier acceptance control register (CANIDAC)
— MSCAN identifier acceptance registers (CANIDAR0–CANIDAR7)
— MSCAN identifier mask registers (CANIDMR0–CANIDMR7)
The TXCAN is immediately forced to a recessive state when the MSCAN goes into the power
down mode or initialization mode (see
Section 8.4.4.5, “MSCAN Initialization
The MSCAN enable bit (CANE) is writable only once in normal system operation modes, which
provides further protection against inadvertently disabling the MSCAN.
Oscillator Clock
shows the structure of the MSCAN clock generation circuitry.
Bus Clock
Protocol Violation Protection
Clock System
(CANCTL0)”) serve as a lock to protect the following registers:
Figure 8-43. MSCAN Clocking Scheme
S12P-Family Reference Manual, Rev. 1.13
CLKSRC
Section 8.4.5.6, “MSCAN Power Down
Mode”).
CANCLK
Freescale’s Scalable Controller Area Network (S12MSCANV3)
MSCAN
CLKSRC
Prescaler
(1 .. 64)
Section 8.3.2.1, “MSCAN Control
Time quanta clock (Tq)
Mode,” and
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