
NUC970 Technical Reference Manual
Publication Release Date: Dec. 15, 2015
- 528 -
Revision V1.30
NUC97
0
T
E
CHNIC
A
L
RE
F
E
RE
N
CE
MA
NUA
L
I2C n Control and Status Register (I2Cn_CSR)
Register
Offset
R/W
Description
Reset Value
I2Cn_CSR
n=0,1
0x000
R/W
I2C n Control and Status Register
0x0000_0000
31
30
29
28
27
26
25
24
Reserved
23
22
21
20
19
18
17
16
Reserved
15
14
13
12
11
10
9
8
Reserved
I2C_RxACK
I2C_BUSY
I2C_AL
I2C_TIP
7
6
5
4
3
2
1
0
Reserved
Tx_NUM
Reserved
IF
IE
I2C_EN
Bits
Description
[31:12]
Reserved
Reserved.
[11]
I2C_RxACK
Received Acknowledge From Slave (Read Only)
This flag represents acknowledge from the addressed slave.
0 = Acknowledge received (ACK).
1 = Not acknowledge received (NACK).
[10]
I2C_BUSY
I
2
C Bus Busy (Read Only)
0 = After STOP signal detected.
1 = After START signal detected.
[9]
I2C_AL
Arbitration Lost (Read Only)
This bit is set when the I
2
C core lost arbitration. Arbitration is lost when:
A STOP signal is detected, but no requested.
The master drives SDA high, but SDA is low.
[8]
I2C_TIP
Transfer in Progress (Read Only)
0 = Transfer complete.
1 = Transferring data.
NOTE:
When a transfer is in progress, you will not allow writing to any register of the I
2
C
master core except SWR.
[5:4]
Tx_NUM
Transmit Byte Counts
These two bits represent how many bytes are remained to transmit. When a byte has
been transmitted, the Tx_NUM will decrease 1 until all bytes are transmitted (Tx_NUM =
0x0) or NACK received from slave. Then the interrupt signal will assert if IE was set.
0x0 = Only one byte is left for transmission.
0x1 = Two bytes are left to for transmission.
0x2 = Three bytes are left for transmission.
0x3 = Four bytes are left for transmission.