MC68HC11E1CFN3R2 Freescale Semiconductor, MC68HC11E1CFN3R2 Datasheet - Page 117

MC68HC11E1CFN3R2

Manufacturer Part Number
MC68HC11E1CFN3R2
Description
Manufacturer
Freescale Semiconductor
Datasheet

Specifications of MC68HC11E1CFN3R2

Cpu Family
HC11
Device Core Size
8b
Frequency (max)
3MHz
Interface Type
SCI/SPI
Program Memory Type
ROMLess
Program Memory Size
Not Required
Total Internal Ram Size
512Byte
# I/os (max)
38
Number Of Timers - General Purpose
8
Operating Supply Voltage (typ)
3.3/5V
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
3V
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
52
Package Type
PLCC
Lead Free Status / Rohs Status
Not Compliant
Receiver Flags
TDRE and TC flags are normally set when the transmitter is first enabled (TE set to 1). The TDRE flag
indicates there is room in the transmit queue to store another data character in the TDR. The TIE bit is
the local interrupt mask for TDRE. When TIE is 0, TDRE must be polled. When TIE and TDRE are 1, an
interrupt is requested.
The TC flag indicates the transmitter has completed the queue. The TCIE bit is the local interrupt mask
for TC. When TCIE is 0, TC must be polled. When TCIE is 1 and TC is 1, an interrupt is requested.
Writing a 0 to TE requests that the transmitter stop when it can. The transmitter completes any
transmission in progress before actually shutting down. Only an MCU reset can cause the transmitter to
stop and shut down immediately. If TE is written to 0 when the transmitter is already idle, the pin reverts
to its general-purpose I/O function (synchronized to the bit-rate clock). If anything is being transmitted
when TE is written to 0, that character is completed before the pin reverts to general-purpose I/O, but any
other characters waiting in the transmit queue are lost. The TC and TDRE flags are set at the completion
of this last character, even though TE has been disabled.
7.9 Receiver Flags
The SCI receiver has five status flags, three of which can generate interrupt requests. The status flags
are set by the SCI logic in response to specific conditions in the receiver. These flags can be read (polled)
at any time by software. Refer to
Figure
7-10, which shows SCI interrupt arbitration.
When an overrun takes place, the new character is lost, and the character that was in its way in the
parallel RDR is undisturbed. RDRF is set when a character has been received and transferred into the
parallel RDR. The OR flag is set instead of RDRF if overrun occurs. A new character is ready to be
transferred into RDR before a previous character is read from RDR.
The NF and FE flags provide additional information about the character in the RDR, but do not generate
interrupt requests.
The last receiver status flag and interrupt source come from the IDLE flag. The RxD line is idle if it has
constantly been at logic 1 for a full character time. The IDLE flag is set only after the RxD line has been
busy and becomes idle, which prevents repeated interrupts for the whole time RxD remains idle.
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor
117

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