Fujitsu FR60 Hardware Manual page 492

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CHAPTER 16 I C INTERFACE
❍ Other Items
1. Addressing after arbitration lost occurs
After arbitration lost occurs, check whether or not the local device is addressed using
software.
When arbitration lost occurs, the device becomes a slave in terms of hardware. However,
after one-byte transfer is completed, both the CLK and DATA lines are set to "L" level. Thus,
if the device is not addressed, immediately open the CLK and DATA lines. If the device is
addressed, open the CLK and DATA lines after preparing for slave transmission or reception
(All of these things must be processed using software).
2. Interrupt condition when one-byte transfer is completed
An interrupt source is generated on I
interrupt condition is met.
Since multiple interrupt conditions must be checked by one interrupt, each of the flags must
be checked by the interrupt routine. The following lists the interrupt conditions used when
one-byte transfer is completed:
• The device is a bus master.
• The device is an addressed slave.
• A general call address is received.
• Arbitration lost occurs.
3. Arbitration lost and interrupt source
When arbitration lost is detected, an interrupt source is generated, not immediately but after
one-byte transfer is completed.
When arbitration lost is detected, the device becomes a slave in terms of hardware.
However, in slave mode, a total of nine clocks must be output before an interrupt source can
be generated. Thus, since an interrupt source is not immediately generated, no processing
can be performed after arbitration lost occurs.
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C bus when one-byte transfer is completed or when an