UPSD3212A Datasheet, PDF (72/163 Pages) STMicroelectronics – Flash Programmable System Devices with 8032 MCU with USB and Programmable Logic

uPSD3212A, uPSD3212C, uPSD3212CV
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
SDA1
SCL1
7
0
Slave Address
7
0
Shift Register
Arbitration and Sync. Logic
Bus Clock Generator
7
0
Control Register
7
0
Status Register
Table 50. Serial Control Register (S2CON)
7
6
5
4
3
2
CR2
ENII
STA
STO
ADDR
AA
AI07430
1
CR1
0
CR0
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