UPSD3354DV-40U6 Datasheet, PDF (134/272 Pages) STMicroelectronics – fast 8032 MCU with programmable logic

I²C interface
UPSD33xx
Table 84.
I²C Bus
speed,
f_SCL
S1SETUP examples for various I²C bus speeds and oscillator frequencies
Parameter
6 MHz
Oscillator frequency, f_OSC
12 MHz
24 MHz
33 MHz
40 MHz
Recommended
S1SETUP Value
93h
A7h
CFh
EEh
FFh
Standard ^{Number of Samples}
Time Between Samples
20
166.6ns
40
83.3ns
80
41.6ns
111
30ns
128
25ns
Total Sampled Period
3332ns
3332ns
3332ns
3333ns
3200ns
Recommended
S1SETUP Value
82h
85h
8Bh
90h
93h
Fast ^{Number of Samples}
Time Between Samples
3
166.6ns
6
83.3ns
12
41.6ns
17
30ns
20
25ns
Total Sampled Period
500ns
500ns
500ns
510ns
500ns
Recommended
(1)
) _{S1SETUP Value}
ct(s ^{High Number of Samples}
-
u _{Time Between Samples}
-
rod ^{Total Sampled Period}
-
P 1. Not compatible with high Speed I²C.
80
1
83.3ns
83.3
82
3
41.6ns
125ns
83
4
30ns
120ns
84
5
25ns
125ns
Obsolete ^{Product(s) - Obsolete 23.13}
I²C operating sequences
The following pseudo-code explains hardware control for these I²C functions on the
UPSD33xx:
● Initialize the Interface
● Function as Master-Transmitter
● Function as Master-Receiver
● Function as Slave-Transmitter
● Function as Slave-Receiver
● Interrupt Service Routine
Full C code drivers for the UPSD33xx I²C interface, and other interfaces are available from
the web at www.st.com/mcu.
Initialization after a UPSD33xx reset
Ensure pins P3.6 and P3.7 are GPIO inputs
● SFR P3.7 = 1 and SFR P3.6 = 1
Configure pins P3.6 and P3.7 as I2C
● SFR P3SFS.6 = 1 and P3SFS.7 = 1
Set I2C clock prescaler to determine fSCL
● SFR S1CON.CR[2:0] = desired SCL freq.
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Doc ID 9685 Rev 7