M37221M4H_15 Datasheet, PDF (40/114 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER with ON-SCREEN DISPLAY CONTROLLER

M37221M4H/M6H/M8H/MAH–XXXSP/FP M37221EASP/FP
(8) Bit 7: Communication mode specification bit
(master/slave specification bit: MST)
This bit is used for master/slave specification in data communica-
tions. When this bit is “0,” the slave is specified, so that a START
condition and a STOP condition generated by the master are received,
and data communication is performed in synchronization with the
clock generated by the master. When this bit is “1,” the master is
specified and a START condition and a STOP condition are gener-
ated, and also the clocks required for data communication are gen-
erated on the SCL.
The MST bit is cleared to “0” in any of the following conditions.
• Immediately after completion of 1-byte data transmission when
arbitration lost is detected
• When a STOP condition is detected.
• When occurence of a START condition is disabled by the START
condition duplication prevention function (Note).
• At reset
Note: The START condition duplication prevention function disables the START
condition generation, bit counter reset, and SCL output, when the follow-
ing condition is satisfied:
a START condition is set by another master device.
I²C Status Register
b7 b6 b5 b4 b3 b2 b1 b0
I²C status register (S1) [Address 00D916]
B
Name
Functions
After reset R W
0 Last receive bit (LRB)
(See note)
0 : Last bit = “0 ”
1 : Last bit = “1 ”
Indeterminate _{R —}
(See note)
1 General call detecting flag 0 : No general call detected
0 _R—
(AD0) (See note)
1 : General call detected _{(See note)}
2 Slave address comparison 0 : Address mismatch
0 _R—
flag (AAS) (See note)
1 : Address match
(See note)
3 Arbitration lost detecting flag 0 : Not detected
(AL) (See note)
1 : Detected
0 _R—
(See note)
4 I2C-BUS interface interrupt
request bit (PIN)
0 : Interrupt request issued
1 : No interrupt request issued
1 _RW
5 Bus busy flag (BB)
0 : Bus free
1 : Bus busy
0 _RW
6, 7 Communication mode
specification bits
(TRX, MST)
b7 b6
0 0 : Slave recieve mode
0 1 : Slave transmit mode
1 0 : Master recieve mode
1 1 : Master transmit mode
0 _RW
Note : These bits and flags can be read out, but cannnot be written.
Fig. 8.6.7 I²C Status Register
SCL
PIN
IICIRQ
Fig. 8.6.8 Interrupt Request Signal Generation Timing
Rev.1.00 Oct 01, 2002 page 38 of 110
REJ03B0134-0100Z