HT46RU22 Holtek Semiconductor Inc., HT46RU22 Datasheet - Page 26

• Manufacturer Part Number: HT46RU22
• Description: Ht46ru22 -- A/d Type 8-bit Mcu
• Manufacturer: Holtek Semiconductor Inc.

Start Signal
The START signal is generated only by the master de-
vice. The other device in the bus must detect the START
signal to set the I
nal is SDA line from high to low, when SCL is high.
Slave Address
The master must select a device for transferring the
data by sending the slave device address after the
START signal. All device in the I
I
slave address (7 bits). If the slave address is matched,
the slave device will generate an interrupt and save the
following bit (8th bit) to SRW bit and sends an acknowl-
edge bit (low level) to the 9th bit. The slave device also
sets the status flag (HAAS), when the slave address is
matched.
Rev. 1.20
2
C Bus slave address (7 bits) to compare with its own
2
C Bus busy bit (HBB). The START sig-
Start Bit
2
C Bus will receive the
I
2
C Communication Timing Diagram
26
In interrupt subroutine, check HAAS bit to know whether
the I
matched or a data byte transfer is completed. When the
slave address is matched, the device must be in trans-
mit mode or receive mode and write data to HDR or
dummy read from HDR to release the SCL line.
SRW Bit
The SRW bit means that the master device wants to
read from or write to the I
check this bit to understand itself if it is a transmitter or a
receiver. The SRW bit is set to 1 means that the mas-
ter wants to read data from the I
vice must write data to a bus as a transmitter. The SRW
is cleared to 0 means that the master wants to write
data to the I
from the I
2
C Bus interrupt comes from a slave address that is
2
C Bus as a receiver.
2
C Bus, so the slave device must read data
2
C Bus. The slave device
2
C Bus, so the slave de-
HT46RU22
March 23, 2007