M16C28 Datasheet, PDF (297/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
16. MULTI-MASTER I²C bus INTERFACE
16.13 Address Data Communication
This section describes data transmit control when a master transferes data or a slave receives data in 7-bit
address format. Figure 16.20 (1) shows a master transmit format.
(1) A master transmit device transmits data to a receive device
S
Slave address R/W A
Data A
Data A/A P
7 bits
“0”
1 - 8 bits
1 - 8 bits
(2) A master receive device receives data from a transmit device
S
Slave address R/W A
Data A
Data
AP
7 bits
“1”
1 - 8 bits
1 - 8 bits
S : START condition
A : ACK bit
P : STOP condition
R/W : Read/Write bit
Figure 16.20 Address data communication format
16.13.1 Example of Master Transmit
For example, a master transmits data as shown below when following conditions are met: standard clock
mode, SCL clock frequency of 100kHz and ACK clock added.
1) Set s slave address to the 7 high-order bits in the S0D0 register
2) Set “8516” to the S20 register, “0002” to the ICK4 to ICK2 bits in the S4D0 register and “0016” to the
S3D0 registe to generate an ACK clock and set SCL clock frequency t 100 kHz (f1=8MHz, fIIC=f1)
3) Set “0016” to the S10 register to reset transmit/receive
4) Set “0816” to the S1D0 register to enable data communication
5) Confirm whether the bus is free by BB flag setting in the S10 register
6) Set “E016” to the S10 register to enter START condition standby mode
7) Set the destination address in 7 high-order bits and "0" to a least significant bit in the S00 register
to generate START condition. At this time, the first byte consisting of SCL and ACK clock are
automatically generated
8) Set a transmit data to the S00 register. At this time, SCL and an ACK clock are automatically
generated
9) When transmitting more than 1-byte control data, repeat the above step 8).
10) Set “C016” in the S10 register to enter STOP condition standby mode if ACK is not returned from
the slave receiver or if the transmit is completed
11) Write dummy data to the S00 regiser to generate STOP condition
Rev. 2.00 Jan. 31, 2007 ^{page 277} of 385
REJ09B0047-0200