CHAPTER 12 SERIAL INTERFACE FUNCTION
Preliminary User’s Manual U15905EJ1V0UD
315
(a) Starting procedure
The procedure to start continuous transmission is shown below.
Figure 12-7. Continuous Transmission Starting Procedure
TXDn (output)
Data (1)
Data (2)
<5>
<1>
<2>
<4>
INTSTn (output)
TXBn register
FFH
FFH
Data (1)
Data (2)
Data (3)
Data (1)
Data (2)
Data (3)
<3>
ASIFn register
(TXBFn, TXSFn bits)
00
10
11
01
01
11
01
11
TXSn 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 TXBFn and TXSFn bits of the
ASIFn register simultaneously, 11 or 00 may be read. Thus, whether writing to the TXBn register is
enabled or not should be judged only for the TXBFn bit.
ASIFn Register
Transmission Starting Procedure
Internal Operation
TXBFn
TXSFn
•
Set transmission mode
<1> Start transmission unit
0
0
•
Write data (1)
1
0
<2> Generate start bit
•
Read ASIFn register (confirm that TXBFn 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> INTSTn interrupt occurs
•
Read ASIFn register (confirm that TXBFn bit = 0)
0
0
1
1
•
Write data (3)
<4> Generate start bit
Start data (2) transmission
<<Transmission in progress>>
1
1
<5> INTSTn interrupt occurs
•
Read ASIFn register (confirm that TXBFn bit = 0)
0
0
1
1
•
Write data (4)
1
1
Note
Transition period
Summary of Contents for V850ES/SA2 UPD703201
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