MC68HC705X32CFU Freescale Semiconductor, MC68HC705X32CFU Datasheet - Page 119

• Manufacturer Part Number: MC68HC705X32CFU
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC705X32CFU

• Cpu Family: HC05
• Device Core Size: 8b
• Frequency (max): 4MHz
• Interface Type: SCI
• Program Memory Type: EPROM
• Program Memory Size: 32KB
• Total Internal Ram Size: 528Byte
• # I/os (max): 32
• Number Of Timers - General Purpose: 1
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• On-chip Adc: 8-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 64
• Package Type: PQFP
• Lead Free Status / Rohs Status: Supplier Unconfirmed

Freescale Semiconductor, Inc.
OR — Overrun error flag
This bit is set when a new byte is ready to be transferred from the receiver shift register to the
receiver data register and the receive data register is already full (RDRF bit is set). Data transfer
is inhibited until the RDRF bit is cleared. Data in the serial communications data register is valid in
this case, but additional data received during an overrun condition (including the byte causing the
overrun) will be lost.
The OR bit is cleared when the serial communications status register is accessed (with OR set)
followed by a read of the serial communications data register.
NF — Noise error flag
This bit is set if there is noise on a ‘valid’ start bit, any of the data bits or on the stop bit. The NF bit
is not set by noise on the idle line nor by invalid start bits. If there is noise, the NF bit is not set until
the RDRF flag is set. Each data bit is sampled three times as described in
Section
7.7.
The NF bit represents the status of the byte in the serial communications data register. For the byte
being received (shifted in) there will be also a ‘working’ noise flag, the value of which will be
transferred to the NF bit when the serial data is loaded into the serial communications data
register. The NF bit does not generate an interrupt because the RDRF bit gets set with NF and can
7
be used to generate the interrupt.
The NF bit is cleared when the serial communications status register is accessed (with NF set)
followed by a read of the serial communications data register.
FE — Framing error flag
This bit is set when the word boundaries in the bit stream are not synchronized with the receiver
bit counter (generated by the reception of a logic zero bit where a stop bit was expected). The FE
bit reflects the status of the byte in the receive data register and the transfer from the receive shift
register to the receive data register is inhibited by an overrun. The FE bit is set during the same
cycle as the RDRF bit but does not get set in the case of an overrun (OR). The framing error flag
inhibits further transfer of data into the receive data register until it is cleared.
The FE bit is cleared when the serial communications status register is accessed (with FE set)
followed by a read of the serial communications data register.
MC68HC05X16
SERIAL COMMUNICATIONS INTERFACE
For More Information On This Product,
7-17
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