MC68HC711E9FU Freescale Semiconductor, MC68HC711E9FU Datasheet - Page 115

• Manufacturer Part Number: MC68HC711E9FU
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC711E9FU

• Cpu Family: HC11
• Device Core Size: 8b
• Frequency (max): 4MHz
• Interface Type: SCI/SPI
• Program Memory Type: EPROM
• Program Memory Size: 12KB
• 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: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 64
• Package Type: PQFP
• Lead Free Status / Rohs Status: Not Compliant

SCR[2:0] — SCI Baud Rate Select Bits
Freescale Semiconductor
Selects receiver and transmitter bit rate based on output from baud rate prescaler stage. Refer to
Figure 7-8
The prescaler bits, SCP[2:0], determine the highest baud rate, and the SCR[2:0] bits select an
additional binary submultiple (÷1, ÷2, ÷4, through ÷128) of this highest baud rate. The result of these
two dividers in series is the 16X receiver baud rate clock. The SCR[2:0] bits are not affected by reset
and can be changed at any time, although they should not be changed when any SCI transfer is in
progress.
Figure 7-8
the highest baud rate. The rate select bits determine additional divide by two stages to arrive at the
receiver timing (RT) clock rate. The baud rate clock is the result of dividing the RT clock by 16.
and
and
Figure 7-9
Figure
XTAL
EXTAL
Figure 7-8. SCI Baud Rate Generator Block Diagram
7-9.
CLOCK GENERATOR
illustrate the SCI baud rate timing chain. The prescaler select bits determine
OSCILLATOR
AND
(÷4)
M68HC11E Family Data Sheet, Rev. 5.1
AS
E
÷
÷
÷
÷
÷
÷
÷
2
2
2
2
2
2
2
0:0
SCR[2:0]
0:0:0
0:0:1
0:1:0
0:1:1
1:0:0
1:0:1
1:1:0
1:1:1
÷
3
INTERNAL BUS CLOCK (PH2)
0:1
÷
4
1:0
BAUD RATE
BAUD RATE
TRANSMIT
RECEIVE
÷
(16X)
÷
(1X)
SCI
SCI
13
16
1:1
SCP[1:0]
SCI Registers
115