R01UH0092EJ0110 Rev.1.10
Page 539 of 807
Jul 31, 2012
M16C/64C Group
25. Multi-master I
2
C-bus Interface
25.2.2
I2C0 Data Shift Register (S00)
When the I
2
C interface is a transmitter, write transmit data to the S00 register. When the I
2
C interface is
a receiver, received data can be read from the S00 register. In master mode, this register is also used to
generate a start condition or stop condition on a bus. (Refer to 25.3.2 “Generating a Start Condition”
and 25.3.3 “Generating a Stop Condition”.)
Write to the S00 register when the ES0 bit in the S1D0 register is 1 (I
2
C interface enabled).
Do not write to the S00 register when transmitting/receiving data.
When the I
2
C interface is a transmitter, the data in the S00 register is transmitted to other devices. The
MSB (bit 7) is transmitted first, synchronizing with the SCLMM clock. Every time 1-bit data is output, the
S00 register value is shifted 1 bit to the left.
When the I
2
C interface is a receiver, data is transferred to the S00 register from other devices. The LSB
(bit 0) is input first, synchronizing with the SCLMM clock. Every time 1-bit data is output, the S00
register value is shifted 1 bit to the left. Figure 25.2 shows Timing to Store Received Data to the S00
Register.
Figure 25.2
Timing to Store Received Data to the S00 Register
b7
I2C0 Data Shift Register
Symbol
S00
Address
02B0h
RW
Reset Value
XXh
b0
Function
Transmit/receive data is stored.
RW
SCLMM
SDAMM
Internal SCL
Shift clock
(internal signal)
Internal SDA
tdfil
tdfil
tdsft
Data is stored to bit 0 at the rising edge of shift clock.
Data
Data
S00 register
tdfil: Noise filter delay time, one to two fVIIC cycles
tdsft: Shift clock delay time, one fVIIC cycle
Register value is shifted 1 bit to the left.
Содержание M16C Series
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