M16C65 Datasheet, PDF (639/829 Pages) Renesas Technology Corp – RENESAS MCU M16C FAMILY / M16C/60

Under development
M16C/65 Group
Preliminary Specification
This is a preliminary specification and is subject to change.
25. Multi-Master I²C-bus Interface
25.3.6 Arbitration Lost
When the following conditions are all met, the signal level of SDAMM pin becomes low by an external
device and the I²C interface determines that it has lost arbitration.
(1) Transmit/receive (one of the following)
• Slave address transmit in master-transmitter mode or master-receiver mode
• Data transmit (ACK clock not included) in master-transmitter mode
• Start condition generated in master-transmitter mode or master-receiver mode
• Stop condition generated in master-transmitter mode or master-receiver mode
(2) Internal SDA output: High
(3) SDAMM pin level: Low (sampling at the rising edge of the clock of SCLMM pin.)
Figure 25.12 shows Operation Example When Arbitration Lost is Detected.
During slave address transmission for example:
SCLMM
Slave address
1
2
3
4
5
6
7
ACK
clock
9
SDAMM
Internal SDA
output
AL bit in the S10 regiser
PIN bit in the S10 regiser
Levels matched
SDA line open
Levels not matched
Arbitration lost detected
TRX bit in the S10 regiser
MST bit in the S10 regiser
IR bit in the IICIC register
Set to 0 by interrupt request acceptance or by a program
Figure 25.12 Operation Example When Arbitration Lost is Detected
When arbitration lost is detected,
• The AL bit in the S10 register becomes 1 (arbitration lost detected)
• Internal SDA output becomes high. (SDAMM becomes high-impedance)
• Slave-receiver mode is entered by setting the TRX bit in the S10 register to 0 (receive mode) and
the MST bit in the S10 register to 0 (slave mode).
In order to write the AL bit to 0 again after arbitration lost is detected, set a value to the S00 register.
When arbitration is lost in slave address transmission, the I²C interface enters the slave-receiver mode
automatically and receives slave address which sent from another master. When the ALS bit in the
S1D0 register is 1 (addressing format), slave address comparison result is determined by reading bits
ADR0 and AAS in the S10 register
When arbitration is lost during data transmission, slave-receiver mode is automatically entered.
REJ09B0484-0030 Rev.0.30 Sep 09, 2008
Page 604 of 791