Holtek HT67F2350 Manual page 191

HT67F2350/HT67F2360
HT67F2370/HT67F2390
Advanced A/D Flash MCU with LCD & EEPROM
I C Bus Communication
2
Communication on the
transmission, a data transmission and finally a STOP signal. When a START signal is placed on
the I C bus, all devices on the bus will receive this signal and be notified of the imminent arrival of
2
data on the bus. The first seven bits of the data will be the slave address with the first bit being the
MSB. If the address of the slave device matches that of the transmitted address, the HAAS bit in the
SIMC1 register will be set and an I
routine, the slave device must first check the condition of the HAAS and SIMTOF bits to determine
whether the interrupt source originates from an address match, 8-bit data transfer completion or
I C bus time-out occurrence. During a data transfer, note that after the 7-bit slave address has been
2
transmitted, the following bit, which is the 8
the SRW bit. This bit will be checked by the slave device to determine whether to go into transmit or
receive mode. Before any transfer of data to or from the I
the bus; the following are steps to achieve this:
• Step 1
Set the SIM2~SIM0 bits to "110" and SIMEN bit to "1" in the SIMC0 register to enable the I
bus.
• Step 2
Write the slave address of the device to the
• Step 3
Set the SIME and SIM Multi-Function interrupt enable bit of the interrupt control register to
enable the SIM interrupt and Multi-function interrupt.
Rev. 1.60
I C bus requires four separate steps, a START signal, a slave device address
2
C interrupt will be generated. After entering the interrupt service
2
bit, is the read/write bit whose value will be placed in
th
I C
2
Start
Set SIM[2:0]=110
Set SIMEN
Write Slave
Address to SIMA
No
2
I C Bus
Interrupt=?
CLR SIME
Poll SIMF to decide when
2
to go to I C Bus ISR
Goto Main Program
I C Bus Initialisation Flow Chart
2
191
C bus, the microcontroller must initialise
2
bus address register SIMA.
Yes
SET SIME and MFnE
Wait for Interrupt
Goto Main Program
C
2
May 16, 2019