CHAPTER 19 IEBus CONTROLLER (V850/SB2)
User’s Manual U13850EJ4V0UM
490
19.5.5 Interval of occurrence of interrupt for IEBus control
Each control interrupt must occur at each point of communication and perform the necessary processing until the
next interrupt occurs. Therefore, the CPU must control the IEBus control block, taking the shortest time of this
interrupt into consideration.
The locations at which the following interrupts may occur are indicated by
↑
in the field where it may occur.
↑
does
not mean that the interrupt occurs at each of the points indicated by
↑
. If an error interrupt (timing error, parity error,
or ACK error) occurs, the IEBus internal circuit is initialized. As a result, the following interrupt does not occur in that
communication frame.
(1) Master transmission
Figure 19-34. Master Transmission (Interval of Interrupt Occurrence)
Start bit
T
t1
T
Broad-
casting
Master address
T
t2
P
Slave address
T
P A
A
T
T
t3
Control
P A
A
t4
T
A
T
Telegraph
length
P A
Data
P
A
Communication
starts
Communication
start interrupt
P
A
Data
Data
A
P
Data
T
T
t4
End of communication
End of frame
U
U
t5
A
Remarks 1.
T: Timing error
A: ACK error
U: Underrun error
: Data set interrupt (INTIE1)
2.
End of frame occurs at the end of 32-byte data.
(IEBus: at 6.29 MHz)
Item
Symbol
MIN.
Unit
Communication starts – timing error
t1
Approx. 93
µ
s
Communication starts – communication start interrupt
t2
Approx. 1282
µ
s
Communication start interrupt – timing error
t3
Approx. 15
µ
s
Communication start interrupt – end of communication
t4
Approx. 1012
µ
s
Transmission data request interrupt interval
t5
Approx. 375
µ
s
Содержание MPD703030A
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