uPSD3212A, uPSD3212C, uPSD3212CV
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I2C INTERFACE
The serial port supports the twin line I2C-bus, con-
sisting of a data line (SDA1), and a clock line
(SCL1) as shown in Figure 39. Depending on the
configuration, the SDA1 and SCL1 lines may re-
quire pull-up resistors.
These lines also function as I/O port lines if the I2C
bus is not enabled.
The system is unique because data transport,
clock generation, address recognition, and bus
control arbitration are all controlled by hardware.
The I2C serial I/O has complete autonomy in byte
handling and operates in 4 modes.
Master transmitter
Master receiver
Slave transmitter
Slave receiver
These functions are controlled by the SFRs (see
Tables 50, 51, and Table 52., page 73):
S2CON: the control of byte handling and the
operation of 4 mode.
S2STA: the contents of its register may also
be used as a vector to various service
routines.
S2DAT: data shift register.
S2ADR: slave address register. Slave
address recognition is performed by On-Chip
H/W.
Figure 39. Block Diagram of the I2C Bus Serial I/O
Table 50. Serial Control Register (S2CON)
76543210
CR2 ENII STA STO ADDR AA CR1 CR0
AI07430
SCL1
SDA1
Bus Clock Generator
Arbitration and Sync. Logic
Shift Register
Status Register
70
Slave Address
70
Control Register
70
70
Internal Bus