SM8954B
8-Bit Micro-controller
16KB Flash
& 1KB RAM embedded
only)
RESTART: This bit only set by master mode. The master will send a start signal then send
TWSIA after the ACK signal when this bit setting. If NAKIF was set (the NACK
signal was received), the master mode will release, and this bit will clear.
(Master mode only)
MRW: This bit is determined the data transmit direction. And this bit will transmit to
bus as bit0 at Address (Address is collection TWSIA [7:1] and MRW as 8 bits
data). When clear this bit the master is in transmits mode and clear is in
receive mode.
Mnemonic: TWSITXD
Address: C4h
7
6
5
4
3
2
1
0
Reset
TXD.7
TXD.6
TXD.5
TXD.4
TXD.3
TXD.2
TXD.1
TXD.0
FFh
The data written into this register will be automatically downloaded to the shift register when the module detects a
calling address is matched and the bit 0 of the received data is one (Slave transmit mode) or when the data in the
shift register has been transmitted with received acknowledge bit (RXAK) =0 in transmit mode.
Mnemonic: TWSIRXD
Address: C5h
7
6
5
4
3
2
1
0
Reset
RXD.7
RXD.6
RXD.5
RXD.4
RXD.3
RXD.2
RXD.1
RXD.0
00h
The TWSI Receive Data Buffer (TWSIRXD) contains the last received data when the MATCH flag is one or the
calling address from master when the MATCH flag is zero. The TWSIRXD register will be updated after a data byte
is received and the previous received data had been read out, otherwise the TWSI module will pull down to SCL
line to inhabit the next data transfer. It is a read-only register. The read operation of this register will clear the RXIF
flag. After the RXIF flag is cleared, the register can load the received data again and set the RXIF flag to generate
interrupt request for reading the newly received data.
Mnemonic: IFR
Address: AAh
7
-
6
-
5
-
4
-
3
-
2
-
1
0
-
Reset
00h
TWSIIF
TWSIIF: It is the logic-ORed result of following TWSI flags : RXIF, TXIF, TFIF and
NAKIF. Firmware can poll this bit to check whether TWSI’s flag is set. (Read
only)
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M083 Ver A SM8954B 3/7/2014
- 48 -
SYNCMOS [ SYNCMOS TECHNOLOGIES,INC ]
