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Rev. 1.00
184 of ���
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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
I2C Serial Interface
I
2
C Status Codes
The I2CSTA register reflects the current status of the I
2
C interface. The three least significant bits
of this register are always zero. There are 26 possible status codes, presented in the accompanying
tables. When any one of 25 out of a total of 26 possible I
2
C states is entered, an interrupt is
requested. The only state that does not generate an interrupt is the F8h state. The contents of the
I2CDAT register is only available when an I
2
C interrupt takes place and the SI bit is set high. This
register is read-only and should not be written to by the application program. In the table below, the
term “SLA” means the slave address, “R” means the R/W bit=1 which are transferred together with
the slave address, “W” means the R/W bit=0 transferred together with the slave address.
I
2
C Status in Master Transmitter Mode
Status
Code
Status of the I
2
C
Application software response
Next action taken by
the I
2
C hardware
to/from
I2CDAT
to I2CCON
STA STO SI AA
08H
START condition has been
t�ansmitted
Load SLA+W
X
0
0
X SLA+W will be t�ansmitted; ACK will be �eceived
10H
Repeated START condition
has been t�ansmitted
Load SLA+W
X
0
0
X SLA+W will be t�ansmitted; ACK will be �eceived
Load SLA+W
X
0
0
X SLA+R will be t�ansmitted;
I
�
C will be switched to “Maste� �eceive�” mode
18H
SLA+W has been t�ansmitted;
ACK has been �eceived
Load data b�te 0
0
0
X Data b�te will be t�ansmitted; ACK will be �eceived
No action
1
0
0
X Repeated START will be t�ansmitted;
No action
0
1
0
X STOP condition will be t�ansmitted;
the “STO” flag will be reset
No action
1
1
0
X STOP condition followed b� a START condition
will be transmitted; the “STO” flag will be reset
�0H
SLA+W has been t�ansmitted;
“not ACK” has been �eceived
Load data b�te 0
0
0
X Data b�te will be t�ansmitted; ACK will be �eceived
No action
1
0
0
X Repeated START will be t�ansmitted
No action
0
1
0
X STOP condition will be t�ansmitted;
the “STO” flag will be reset
No action
1
1
0
X STOP condition followed b� a START condition
will be transmitted; the “STO” flag will be reset
�8H
Data b�te in I�CDAT has been
t�ansmitted;
ACK has been �eceived
Load data b�te 0
0
0
X Data b�te will be t�ansmitted;
ACK bit will be �eceived
No action
1
0
0
X Repeated START will be t�ansmitted
No action
0
1
0
X STOP condition will be t�ansmitted;
the “STO” flag will be reset
No action
1
1
0
X STOP condition followed b� a START condition
will be transmitted; STO flag will be reset
30H
Data b�te in I�CDAT has been
t�ansmitted
data b�te
0
0
0
X Data b�te will be t�ansmitted; ACK will be �eceived
No action
1
0
0
X Repeated START will be t�ansmitted;
No action
0
1
0
X STOP condition will be t�ansmitted;
STO flag will be reset
No action
1
1
0
X STOP condition followed b� a START condition
will be transmitted; STO flag will be reset
38H
A�bit�ation lost in SLA+R/W o�
data b�tes
No action
0
0
0
X I
�
C b�s will be �eleased;
the “not add�essed slave” state will be ente�ed
No action
1
0
0
X A START condition will be t�ansmitted when the
b�s becomes f�ee