MC68HC11E Motorola, MC68HC11E Datasheet - Page 129

• Manufacturer Part Number: MC68HC11E
• Description: Microcontrollers
• Manufacturer: Motorola

7.8 Status Flags and Interrupts
M68HC11E Family — Rev. 5
MOTOROLA
The SCI transmitter has two status flags. These status flags can be read by
software (polled) to tell when the corresponding condition exists. Alternatively, a
local interrupt enable bit can be set to enable each of these status conditions to
generate interrupt requests when the corresponding condition is present. Status
flags are automatically set by hardware logic conditions, but must be cleared by
software, which provides an interlock mechanism that enables logic to know when
software has noticed the status indication. The software clearing sequence for
*SCP2 is present only on MC68HC(7)11E20.
XTAL
EXTAL
Freescale Semiconductor, Inc.
For More Information On This Product,
Serial Communications Interface (SCI)
CLOCK GENERATOR
OSCILLATOR
Go to: www.freescale.com
Figure 7-9. MC68HC(7)11E20 SCI Baud Rate
AND
(÷4)
Generator Block Diagram
AS
E
÷
÷
÷
÷
÷
÷
÷
2
2
2
2
2
2
2
0:0:0
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
Serial Communications Interface (SCI)
0:0:1
INTERNAL BUS CLOCK (PH2)
÷
4
0:1:0
Status Flags and Interrupts
÷
BAUD RATE
BAUD RATE
TRANSMIT
RECEIVE
13
(16X)
÷
(1X)
SCI
SCI
0:1:1
16
÷
39
Data Sheet
SCP[2:0]*
1:0:0
129