CHAPTER 19 IEBus CONTROLLER (V850/SB2)
User’s Manual U13850EJ4V0UM
482
19.5 Interrupt Generation Timing and Main CPU Processing
19.5.1 Master transmission
Initial preparation processing:
Sets a unit address, slave address, control data, telegraph length, and the first byte of the transmit data.
Communication start processing:
Sets the bus control register (enables communication, master request, and slave reception).
Figure 19-30. Master Transmission
Start
Broad-
casting
M address P
S address
P
A
Control
P
A
Telegraph
length
P
A
Data 1
P
A
Data 1
Data 2
P
A
Data n – 1
P
A
Data n
P
A
<1>
<2>
Approx. 624 s (mode 1)
Approx. 390 s
(mode 1)
µ
µ
<1> Interrupt (INTIE2) occurrence
Judgment of occurrence of error
→
Error processing
↓
Judgment of slave request
→
Slave reception processing
(See
19.5.1 (1) Slave reception processing
)
↓
Judgment of contention 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
→
Re-communication processing
(See
19.5.1 (3) Recommunication processing
)
Remarks 1.
: Interrupt (INTIE1) occurrence (See
19.5.1 (2) Interrupt (INTIE1) occurrence
)
The transmit data of the second byte and those that follow are written to the IEBus data
register (DR) by DMA transfer.
At this time, the data transfer direction is RAM (memory)
→
SFR (peripheral)
2.
: An interrupt (INTIE1) does not occur.
3.
n = Final number of data bytes
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