HD64F2149 Datasheet, PDF (518/1035 Pages) Renesas Technology Corp – Hitachi 16-Bit Single-Chip Microcomputer

DDCSWR SAR
Bit 6
Bit 0
SARX
Bit 0
SW
FS
FSX
Operating Mode
0
0
0
1
1
0
I²C bus format
• SAR and SARX slave addresses recognized
I²C bus format
(Initial value)
• SAR slave address recognized
• SARX slave address ignored
I²C bus format
• SAR slave address ignored
• SARX slave address recognized
1
Synchronous serial format
• SAR and SARX slave addresses ignored
1
0
0
0
1
Formatless mode (start/stop conditions not detected)
• Acknowledge bit used
1
0
1
1
Formatless mode* (start/stop conditions not detected)
• No acknowledge bit
Note: * Do not set this mode when automatic switching to the I²C bus format is performed by means
of the DDCSWR setting.
16.2.3 Second Slave Address Register (SARX)
Bit
Initial value
Read/Write
7
6
5
4
3
2
1
0
SVAX6 SVAX5 SVAX4 SVAX3 SVAX2 SVAX1 SVAX0 FSX
0
0
0
0
0
0
0
1
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
SARX is an 8-bit readable/writable register that stores the second slave address and selects the
communication format. When the chip is in slave mode (and the addressing format is selected), if
the upper 7 bits of SARX match the upper 7 bits of the first frame received after a start condition,
the chip operates as the slave device specified by the master device. SARX is assigned to the same
address as ICDR, and can be written and read only when the ICE bit is cleared to 0 in ICCR.
SARX is initialized to H'01 by a reset and in hardware standby mode.
Bits 7 to 1—Second Slave Address (SVAX6 to SVAX0): Set a unique address in bits SVAX6 to
SVAX0, differing from the addresses of other slave devices connected to the I²C bus.
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