CHAPTER 10 SERIAL INTERFACE FUNCTION
User’s Manual U13850EJ4V0UM
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10.3.6 Interrupt request (INTIICn) generation timing and wait control
The setting of bit 3 (WTIMn) in IIC control register n (IICCn) determines the timing by which INTIICn is generated
and the corresponding wait control, as shown below (n = 0, 1).
Table 10-4. INTIICn Generation Timing and Wait Control
During Slave Device Operation
During Master Device Operation
WTIMn
Address
Data Reception
Data Transmission
Address
Data Reception
Data Transmission
0
9
Notes 1, 2
8
Note 2
8
Note 2
9
8
8
1
9
Notes 1, 2
9
Note 2
9
Note 2
9
9
9
Notes 1.
The slave device’s INTIICn signal and wait period occurs at the falling edge of the ninth clock only
when there is a match with the address set to slave address register n (SVAn).
At this point, ACK is output regardless of the value set to IICCn’s bit 2 (ACKEn). For a slave device
that has received an extension code, INTIICn occurs at the falling edge of the eighth clock.
2.
If the received address does not match the contents of slave address register n (SVAn), neither
INTIICn nor a wait occurs.
Remarks 1.
The numbers in the table indicate the number of the serial clock’s clock signals. Interrupt requests
and wait control are both synchronized with the falling edge of these clock signals.
2.
n = 0, 1
(1) During address transmission/reception
•
Slave device operation:
Interrupt and wait timing are determined regardless of the WTIMn bit.
•
Master device operation: Interrupt and wait timing occur at the falling edge of the ninth clock regardless of
the WTIMn bit.
(2) During data reception
•
Master/slave device operation: Interrupt and wait timing are determined according to the WTIMn bit.
(3) During data transmission
•
Master/slave device operation: Interrupt and wait timing are determined according to the WTIMn bit.
(4) Wait cancellation method
The four wait cancellation methods are as follows.
•
By setting bit 5 (WRELn) of IIC control register n (IICCn) to 1
•
By writing to IIC shift register n (IICn)
•
By start condition setting (bit 1 (STTn) of IIC control register n (IICCn) = 1)
•
By step condition setting (bit 0 (SPTn) of IIC control register n (IICCn) = 1)
When an 8-clock wait has been selected (WTIMn = 0), the output level of ACK must be determined prior to wait
cancellation.
Remark
n = 0, 1
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