MC68F375BGMZP33 Freescale Semiconductor, MC68F375BGMZP33 Datasheet - Page 289

• Manufacturer Part Number: MC68F375BGMZP33
• Description: IC MPU 32BIT 33MHZ 217-PBGA
• Manufacturer: Freescale Semiconductor

Specifications of MC68F375BGMZP33

• Processor Type: M683xx 32-Bit
• Speed: 33MHz
• Voltage: 5V
• Mounting Type: Surface Mount
• Package / Case: 217-PBGA
• Processor Series: M683xx
• Core: CPU32
• Data Bus Width: 32 bit
• Program Memory Type: Flash
• Program Memory Size: 256 KB
• Data Ram Size: 10 KB
• Interface Type: SPI, SCI, CAN
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 48
• Number Of Timers: 16
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 16 Channel
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Features: -
• Lead Free Status / Rohs Status: No

6.8.7.7 Idle-Line Detection
MC68F375
REFERENCE MANUAL
is synchronized with the MCU system clock. Operation of the receiver state machine
is detailed in the Queued Serial Module Reference Manual (QSMRM/AD).
The number of bits shifted in by the receiver depends on the serial format. However,
all frames must end with at least one stop bit. When the stop bit is received, the frame
is considered to be complete, and the received data in the serial shifter is transferred
to the RDRx. The receiver data register flag (RDRF) is set when the data is
transferred.
The stop bit is always a logic one. If a logic zero is sensed during this bit-time, the FE
flag in SCxSR is set. A framing error is usually caused by mismatched baud rates
between the receiver and transmitter or by a significant burst of noise. Note that a
framing error is not always detected; the data in the expected stop bit-time may hap-
pen to be a logic one.
Noise errors, parity errors, and framing errors can be detected while a data stream is
being received. Although error conditions are detected as bits are received, the noise
flag (NF), the parity flag (PF), and the framing error (FE) flag in SCxSR are not set until
data is transferred from the serial shifter to the RDRx.
RDRF must be cleared before the next transfer from the shifter can take place. If
RDRF is set when the shifter is full, transfers are inhibited and the overrun error (OR)
flag in SCxSR is set. OR indicates that the RDRx needs to be serviced faster. When
OR is set, the data in the RDRx is preserved, but the data in the serial shifter is lost.
When a completed frame is received into the RDRx, either the RDRF or OR flag is
always set. If RIE in SCCxR1 is set, an interrupt results whenever RDRF is set. The
receiver status flags NF, FE, and PF are set simultaneously with RDRF, as appropri-
ate. These receiver flags are never set with OR because the flags apply only to the
data in the receive serial shifter. The receiver status flags do not have separate inter-
rupt enables, since they are set simultaneously with RDRF and must be read by the
user at the same time as RDRF.
When the CPU reads SCxSR and SCxDR in sequence, it acquires status and data,
and also clears the status flags. Reading SCxSR acquires status and arms the clear-
ing mechanism. Reading SCxDR acquires data and clears SCxSR.
During a typical serial transmission, frames are transmitted isochronically and no idle
time occurs between frames. Even when all the data bits in a frame are logic ones, the
start bit provides one logic zero bit-time during the frame. An idle line is a sequence of
contiguous ones equal to the current frame size. Frame size is determined by the state
of the M bit in SCCxR1.
The SCI receiver has both short and long idle-line detection capability. Idle-line detec-
tion is always enabled. The idle-line type (ILT) bit in SCCxR1 determines which type
of detection is used. When an idle-line condition is detected, the IDLE flag in SCxSR
is set.
Freescale Semiconductor, Inc.
QUEUED SERIAL MULTI-CHANNEL MODULE
For More Information On This Product,
Go to: www.freescale.com
Rev. 25 June 03
MOTOROLA
6-55