TMPM330 - Keil

Under development
10.6 Data Transfer Procedure in the I 2 C Bus Mode
10.6.1 Device Initialization
TMPM330 (rev 0.4) 10-19
TMPM330
First, program SBIxCR1 by writing “0” to bits 7 to 5 and bit 3 in SBIxCR1.
Next, program SBIxI2CAR by specifying a slave address at and an address
recognition mode at . ( must be set to”0” when using the addressing format).
Then program SBIxCR2 to initially configure the SBI in the slave receiver mode by writing
“0” to , “1” to , “10” to and “0” to bits 1 and 0.
7 6 5 4 3 2 1 0
SBIxCR1 ← 0 0 0 X 0 X X X Specifies ACK and SCL clock.
SBIxI2CAR ← X X X X X X X X Specifies a slave address and an address recognition
mode.
SBIxCR2 ← 0 0 0 1 1 0 0 0 Configures the SBI as a slave receiver.
(Note) X: Don’t care
10.6.2 Generating the Start Condition and a Slave Address
Master mode
In the master mode, the following steps are required to generate the start condition
and a slave address.
First, ensure that the bus is free ( = “0”). Then, write “1” to SBIxCR1 to
select the acknowledgment mode. Write to SBIxDBR a slave address and a direction
bit to be transmitted.
When = “0,” writing “1111” to SBIxCR2 generates the
start condition on the bus. Following the start condition, the SBI generates nine clocks
from the SCL pin. The SBI outputs the slave address and the direction bit specified at
SBIxDBR with the first eight clocks, and releases the SDA line in the ninth clock to
receive an acknowledgment signal from the slave device.
The INTSBIx interrupt request is generated on the falling of the ninth clock, and
is cleared to ”0.” In the master mode, the SBI holds the SCL line at the “L” level while
is “0.” changes its value according to the transmitted direction bit at
generation of the INTSBIx interrupt request, provided that an acknowledgment signal
has been returned from the slave device.
Settings in main routine
7 6 5 4 3 2 1 0
Reg. ← SBISR
Reg. ← Reg. e 0x20
if Reg.
Then
≠ 0x00 Ensures that the bus is free.
SBIxCR1 ← X X X 1 0 X X X Selects the acknowledgement mode.
SBIxDR1 ← X X X X X X X X Specifies the desired slave address and direction.
SBIxCR2 ← 1 1 1 1 1 0 0 0 Generates the start condition.
Example of INTSBI0 interrupt routine
Clears the interrupt request.
Processing
End of interrupt
Serial Bus Interface (SBI)