mc68hc11e0fnr2 Freescale Semiconductor, Inc, mc68hc11e0fnr2 Datasheet - Page 116

• Manufacturer Part Number: mc68hc11e0fnr2
• Description: Hc11 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Serial Communications Interface (SCI)
7.8 Status Flags and Interrupts
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 these flags is automatic. Functions that are normally
performed in response to the status flags also satisfy the conditions of the clearing sequence.
116
*SCP2 is present only on MC68HC(7)11E20.
XTAL
EXTAL
CLOCK GENERATOR
OSCILLATOR
Figure 7-9. MC68HC(7)11E20 SCI Baud Rate
AND
(÷4)
M68HC11E Family Data Sheet, Rev. 5.1
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
0:0:1
INTERNAL BUS CLOCK (PH2)
÷
4
0:1:0
÷
BAUD RATE
BAUD RATE
TRANSMIT
RECEIVE
13
(16X)
÷
(1X)
SCI
SCI
0:1:1
16
÷
39
Freescale Semiconductor
SCP[2:0]*
1:0:0