UPSD3422_06 Datasheet, PDF (119/293 Pages) STMicroelectronics – Turbo Plus Series Fast Turbo 8032 MCU with USB and Programmable Logic

uPSD34xx
I²C interface
23.6
General call address
A General Call (GC) occurs when a Master-Transmitter initiates a transfer containing a
Slave address of 0000000b, and the R/W bit is logic 0. All Slave devices capable of
responding to this broadcast message will acknowledge the GC simultaneously and then
behave as a Slave-Receiver. The next byte transmitted by the Master will be accepted and
acknowledged by all Slaves capable of handling the special data bytes. A Slave that cannot
handle one of these data bytes must ignore it by not acknowledging it. The I²C specification
lists the possible meanings of the special bytes that follow the first GC address byte, and the
actions to be taken by the Slave device(s) upon receiving them. A common use of the GC by
a Master is to dynamically assign device addresses to Slave devices on the bus capable of a
programmable device address.
The uPSD34xx can generate a GC as a Master-Transmitter, and it can receive a GC as a
Slave. When receiving a GC address (00h), an interrupt will be generated so firmware may
respond to the special GC data bytes if desired.
23.7
Serial I/O engine (SIOE)
At the heart of the I²C interface is the hardware SIOE, shown in Figure 43. The SIOE
automatically handles low-level I²C bus protocol (data shifting, handshaking, arbitration,
clock generation and synchronization) and it is controlled and monitored by five SFRs.
The five SFRs shown in Figure 43 are:
● S1CON - Interface Control (Table 54 on page 121)
● S1STA - Interface Status (Table 56 on page 123)
● S1DAT - Data Shift Register (Table 57 on page 124)
● S1ADR - Device Address (Table 58 on page 124)
● S1SETUP - Sampling Rate (Table 59 on page 125)
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