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I
2
C CONTROLLER
S3C2501X
6-8
6.5 I
2
C SPECIAL REGISTERS
The I
2
C controller has three special registers: a control status register (IICCON), a prescaler register (IICPS), and
a shift buffer register (IICBUF).
6.5.1 CONTROL STATUS REGISTER (IICCON)
The control status register for the I
2
C, IICCON, is described in Table 6-2.
Table 6-1. Control Status Register (IICCON)
Register
Address
R/W
Description
Rest Value
IICCON
0xF00F0000
R/W
Control status register
0x00000000
Table 6-2. IICCON Register Description
Bit Number
Bit Name
Description
[0]
Buffer flag (BF)
The BF bit is set when the buffer is empty in transmit mode or
when the buffer is full in receive mode. To clear the buffer, you
write a "0" to this bit. The BF bit is cleared automatically
whenever the IICBUF register is written or read.
[1]
Interrupt enable (IEN)
Setting the interrupt enable bit to "1" enables the I
2
C interrupt.
An interrupt is generated if BF bit set to 1.
[2]
Last received bit (LRB)
The LRB bit is read only. It holds the value of the last received bit
over the I
2
C. Normally, this bit will be the value of the slave
acknowledgement. To check for slave acknowledgement, you
test the LRB.
[3]
Acknowledge enable (ACK)
The ACK bit is normally set to "1". This causes the I
2
C controller
to send an acknowledge automatically after each byte. This bit
must be "0" when the I
2
C controller is operating in receiver mode
and requires no further data to be received from the slave
transmitter. This causes a negative acknowledge on the I
2
C,
which halts further reception from the slave device.
[5:4]
COND1, COND0
These bits control the generation of the start, stop, and repeat
start conditions: "00" = no effect, "01" = start, "10" = stop, and
"11" = repeat start. When start condition, BF bit should be set
simultaneously. When repeated start condition, ACK bit should
be set simultaneously
[6]
Bus busy (BUSY)
This bit is a read-only flag that indicates when the I
2
C is in use. A
"1" indicates that the bus is busy. This bit is set or cleared by a
start or stop condition, respectively.
[7]
Reset
If "1" is written to the reset bit, the I
2
C controller is reset to its
initial state.
[31:8]
Reserved
Not applicable.
Summary of Contents for S3C2501X
Page 18: ......
Page 275: ...MEMORY CONTROLLER S3C2501X 5 60 NOTES ...
Page 289: ...I2C CONTROLLER S3C2501X 6 14 NOTES ...
Page 373: ...GDMA CONTROLLER S3C2501X 9 24 NOTES ...
Page 435: ...I O PORTS S3C2501X 12 12 NOTES ...