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uPSD3212A, uPSD3212C, uPSD3212CV
Table 51. Description of the S2CON BitsTable 52. Selection of the Serial Clock Frequency SCL in Master Mode
Bit Symbol Function
7CR2
This bit along with Bits CR1and CR0 determines the serial clock frequency when SIO is
in the Master Mode.
6ENII
Enable IIC. When ENI1 = 0, the IIC is disabled. SDA and SCL outputs are in th e high
impedance state.
5STA
START Flag. When this bit is set, the SIO H/W checks the status of the I2C-bus and
generates a START condition if the bus free. If the bus is busy, the SIO will generate a
repeated START condition when this bit is set.
4STO
STOP Flag. With this bit set while in Master Mode a STOP condition is ge nerated.
When a STOP condition is detected on the I2C bus, the I2C hardware clea rs the STO
Flag.
Note: This bit have to be set before 1 cycle interrupt period of STOP. That is, if this bit is
set, STOP condition in Master Mode is generated after 1 cycle inte rrupt period.
3 ADDR This bit is set when address byte was received. Must be cleared by software.
2AA
Acknowledge enable signal. If this bit is set, an acknowledge (low level to SDA) is
returned during the acknowledge clock pulse on the SCL lin e when:
• Own slave address is received
• A data byte is received while the device is programmed to be a Master Rece iver
• A data byte is received while the device is a selected Slave Receiver. When this bit is
reset, no acknowledge is returned.
SIO release SDA line as high during the acknowledge clock pulse.
1CR1
These two bits along with the CR2 Bit determine the serial clock frequency when SIO is
in the Master Mode.
0CR0
CR2 CR1 CR0 fOSC Divisor Bit Rate (kHz) at fOSC
12MHz 24MHz 36MHz 40MHz
0 0 0 16 375 750 X X
0 0 1 24 250 500 750 833
0 1 0 30 200 400 600 666
0 1 1 60 100 200 300 333
1 0 0 120 50 100 150 166
1 0 1 24 0 25 50 75 83
1 1 0 480 12.5 25 37.5 41
1 1 1 960 6.25 12.5 18.75 20