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CHAPTER 18 SERIAL INTERFACE IIC0 (
μ
PD780078Y SUBSERIES ONLY)
User
’
s Manual U14260EJ3V1UD
Figure 18-5. Format of IIC Control Register 0 (IICC0) (4/4)
SPT0
Stop condition trigger
0
Stop condition is not generated.
1
Stop condition is generated (termination of master device
’
s transfer).
After the SDA0 line goes to low level, either set the SCL0 line to high level or wait until it goes to
high level. Next, after the rated amount of time has elapsed, the SDA0 line changes from low level
to high level and a stop condition is generated.
Cautions concerning set timing
For master reception:
Cannot be set during transfer.
Can be set only in the waiting period when ACKE0 has been set to 0 and slave has
been notified of final reception.
A stop condition cannot be generated normally during the ACK0 period. Therefore,
set it during the waiting period.
Cannot be set at the same time as STT0.
SPT0 can be set only when in master mode.
Note
When WTIM0 has been set to 0, if SPT0 is set during the wait period that follows output of eight clocks, note
that a stop condition will be generated during the high level period of the ninth clock.
When a ninth clock must be output, WTIM0 should be changed from 0 to 1 during the wait period following
output of eight clocks, and SPT0 should be set during the wait period that follows output of the ninth clock.
For master transmission:
Condition for clearing (SPT0 = 0)
Condition for setting (SPT0 = 1)
Cleared by loss in arbitration
Automatically cleared after stop condition is detected
Set by instruction
Cleared by LREL0 = 1 (exit from communications)
When IICE0 = 0 (operation stop)
When RESET is input
Note
Set SPT0 only in master mode. However, SPT0 must be set and a stop condition generated before the
first stop condition is detected following the switch to the operation enabled status. For details, see
18.5.14
Other cautions
.
Caution
When bit 3 (TRC0) of IIC status register 0 (IICS0) is set to 1, WREL0 is set during the ninth clock
and wait is canceled, after which TRC0 is cleared and the SDA0 line is set to high impedance.
Remark
Bit 0 (SPT0) becomes 0 when it is read after data setting.