CHAPTER 19 IEBus CONTROLLER (V850/SB2)
User’s Manual U13850EJ4V0UM
484
19.5.2 Master reception
Before performing master reception, it is necessary to notify the slave of slave transmission units. Therefore, more
than two communication frames are necessary for master reception.
The slave unit prepares the transmit data, set (1) the slave transmission enable flag (ENSLVTX), and waits.
Initial preparation processing:
Sets a unit address, slave address, and control data.
Communication start processing:
Sets the bus control register (enables communication and master request).
Figure 19-31. Master Reception
Approx. 1014 s (mode 1)
µ
Start
Broad-
casting
M address
P
S address
P
A
Control
A
P
Telegraph
length
A
P
Data 1
Approx. 390 s
(mode 1)
µ
Data 1
P
A
Data 2
P
A
Data n – 1
P
A
Data n
P
A
< 2 >
< 1 >
<1> Interrupt (INTIE2) occurrence
Judgment of occurrence of error
→
Error processing
↓
Judgment of slave request
→
Slave processing
↓
Judgment of collision result
→
Remaster request processing
<2> Interrupt (INTIE2) occurrence
Judgment of occurrence of error
→
Error processing
↓
Judgment of end of communication
→
End of communication processing
↓
Judgment of end of frame
→
Frame end processing (See
19.5.2 (2) Frame end
processing
)
Remarks 1.
: Interrupt (INTIE1) occurrence (See
19.5.2 (1) Interrupt (INTIE1) occurrence
)
The receive data stored to the IEBus data register (DR) is read by DMA transfer.
At this time, the data transfer direction is SFR (peripheral)
→
RAM (memory).
2.
n = Final number of data bytes