Z8F1601 Datasheet, PDF (132/246 Pages) Zilog, Inc. – Z8 Encore Microcontrollers with Flash Memory and 10-Bit A/D Converter

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14. Software responds by setting the STOP bit of the I²C Control register.
15. If no new data is to be sent or address is to be sent, software responds by clearing the
TXI bit of the I²C Control register.
16. The I²C Controller completes transmission of the data on the SDA signal.
17. The I²C Controller sends the STOP condition to the I²C bus.
Writing a Transaction with a 10-Bit Address
1. The I²C Controller shifts the I²C Shift register out onto SDA signal.
2. The I²C Controller waits for the slave to send an Acknowledge (by pulling the SDA
signal Low). If the slave pulls the SDA signal High (Not-Acknowledge), the I²C
Controller sends a Stop signal.
3. If the slave needs to service an interrupt, it pulls the SCL signal low, which halts I²C
operation.
4. If there is no other data in the I²C Data register or the STOP bit in the I²C Control
register is set by software, then the Stop signal is sent.
The data transfer format for a 10-bit addressed slave is illustrated in the figure below.
Shaded regions indicate data transferred from the I²C Controller to slaves and unshaded
regions indicate data transferred from the slaves to the I²C Controller.
S
Slave Address
1st 7 bits
W=0 A
Slave Address
2nd Byte
A
Data
A
Data A/A P
Figure 80. 10-Bit Addressed Slave Data Transfer Format
The first seven bits transmitted in the first byte are 11110XX. The two bits XX are the two
most-significant bits of the 10-bit address. The lowest bit of the first byte transferred is the
write signal. The transmit operation is carried out in the same manner as 7-bit addressing.
The data transfer format for a transmit operation on a 10-bit addressed slave is as follows:
1. Software asserts the IEN bit in the I²C Control register.
2. Software asserts the TXI bit of the I²C Control register to enable Transmit interrupts.
3. The I²C interrupt asserts because the I²C Data register is empty.
4. Software responds to the TDRE bit by writing the first slave address byte. The least-
significant bit must be 0 for the write operation.
5. Software asserts the START bit of the I²C Control register.
6. The I²C Controller sends the START condition to the I²C slave.
PS017609-0803
I2C Controller