ST90135M5Q6 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST90135M5Q6' PDF : 190 Pages View PDF
ST90158 - SERIAL PERIPHERAL INTERFACE (SPI)
SERIAL PERIPHERAL INTERFACE (Cont’d)
Table 26. Typical I2C-bus Sequences
Phase
INITIA LIZE
START
TR ANSMI SSIO N
ACKNOWLEDGE
STOP
Softw are
SPICR.CPOL, CPHA = 0, 0
SPICR.SPEN = 0
SPICR.BMS = 1
SCK pin set as AF output
SDI pin set as input
Set SDO port bit to 1
SDO pin set as output
Open Drain
Set SDO port bit to 0
SPICR.SPEN = 1
SDO pin as Alternate Func-
tion output load data into
SPIDR
SPICR.SPEN = 0
Poll SDA line
Set SDA line
SPICR.SPEN = 1
SDO pin set as output
Open Drain
SPICR.SPEN = 0
Set SDO port bit to 1
Hardware
SCK, SDO in HI-Z
SCL, SDA = 1, 1
SDA = 0, SCL = 1
interrupt request
SCL = 0
Start transmission
Interrupt request at end of
byte transmission
SCK, SDO in HI-Z
SCL, SDA = 1
SCL = 0
SDA = 1
interrupt request
Notes
Set polarity and phase
SPI disable
START/STO P interrupt
Enable
START condition
receiver START detection
Managed by interrupt rou-
tine load FFh when receiv-
ing end of transmission
detection
SPI disable
only if transmitting
only if receiving
only if transmitting
STOP condition
Figure 68. SPI Data and Clock Timing (for I2C protocol)
SDA
1st BYTE
AcK
th
n BYTE
AcK
SCL
1
2
8
9
1
2
8
9
START
CONDITION
n
CLOCK PULSE
FOR ACKNOWLEDGEMENT
DRIVEN BY SOFTWARE
CLOCK PULSE
FOR ACKNOWLEDGEMENT
DRIVEN BY SW STOP
CONDITION
VR0 0018 8
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9
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