CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U14492EJ3V0UD
431
(a) Starting procedure
The procedure to start continuous transmission is shown below.
Figure 10-5. Continuous Transmission Starting Procedure
TXD0 (output)
Data (1)
Data (2)
<5>
<1>
<2>
<4>
INTST0 (output)
TXB0 register
FFH
FFH
Data (1)
Data (2)
Data (3)
Data (1)
Data (2)
Data (3)
<3>
ASIF0 register
(TXBF0, TXSF0 bits)
00
10
11
01
01
11
01
11
TXS0 register
Start
bit
Stop
bit
Stop
bit
Start
bit
Note
Note
Since this period is a transition period from 10 to 01, when reading the TXBF0 and TXSF0 bits of the
ASIF0 register simultaneously, 11 or 00 may be read. Thus, whether writing to the TXB0 register is
enabled or not should be judged only for the TXBF0 bit.
ASIF0 Register
Transmission Starting Procedure
Internal Operation
TXBF0
TXSF0
•
Set transmission mode
<1> Start transmission unit
0
0
•
Write data (1)
1
0
<2> Generate start bit
•
Read ASIF0 register (confirm that TXBF0 bit = 0)
Start data (1) transmission
1
0
0
0
1/0
Note
1/0
Note
1
1
•
Write data (2)
<<Transmission in progress>>
1
1
<3> INTST0 interrupt occurs
•
Read ASIF0 register (confirm that TXBF0 bit = 0)
0
0
1
1
•
Write data (3)
<4> Generate start bit
Start data (2) transmission
<<Transmission in progress>>
1
1
<5> INTST0 interrupt occurs
•
Read ASIF0 register (confirm that TXBF0 bit = 0)
0
0
1
1
•
Write data (4)
1
1
Note
Transition period
Содержание V850E/IA1 mPD703116
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