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CHAPTER 17 SERIAL INTERFACE IIC0 (
µ
PD780344Y, 780354Y SUBSERIES ONLY)
User’s Manual U15798EJ2V0UD
(2) IIC status register 0 (IICS0)
This register indicates the status of I
2
C.
IICS0 is read by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets IICS0 to 00H.
Figure 17-4. Format of IIC Status Register 0 (IICS0) (1/3)
Address: FFA5H After reset: 00H R
Symbol
7
6
5
4
3
2
1
0
IICS0
MSTS0
ALD0
EXC0
COI0
TRC0
ACKD0
STD0
SPD0
MSTS0
Master device status
0
Slave device status or communication standby status
1
Master device communication status
Condition for clearing (MSTS0 = 0)
Condition for setting (MSTS0 = 1)
• When a stop condition is detected
• When a start condition is generated
• When ALD0 = 1
• Cleared by LREL0 = 1
• When IICE0 changes from 1 to 0
• When RESET is input
ALD0
Detection of arbitration loss
0
This status means either that there was no arbitration or that the arbitration result was a “win”.
1
This status indicates the arbitration result was a “loss”. MSTS0 is cleared.
Condition for clearing (ALD0 = 0)
Condition for setting (ALD0 = 1)
• Automatically cleared after IICS0 is read
Note
• When the arbitration result is a “loss”.
• When IICE0 changes from 1 to 0
• When RESET is input
EXC0
Detection of extension code reception
0
Extension code was not received.
1
Extension code was received.
Condition for clearing (EXC0 = 0)
Condition for setting (EXC0 = 1)
• When a start condition is detected
• When the higher 4 bits of the received
• When a stop condition is detected
address data is either “0000” or “1111”
• Cleared by LREL0 = 1
(set at the rising edge of the eighth clock).
• When IICE0 changes from 1 to 0
• When RESET is input
Note
This register is also cleared when a bit manipulation instruction is executed for bits other than IICS0.
Содержание mPD780344 Series
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