Z8F4822AR020SG Datasheet, PDF (156/323 Pages) Zilog, Inc. – High Performance 8-Bit Microcontrollers

Z8 Encore! XP^® F64xx Series
Product Specification
136
10. The I²C Controller shifts the rest of the first byte of address and write bit out the SDA
signal.
11. If the I²C slave sends an acknowledge by pulling the SDA signal Low during the next
High period of SCL the I²C Controller sets the ACK bit in the I²C Status Register.
Continue with Step 12.

If the slave does not acknowledge the first address byte, the I²C Controller sets the
NCKI bit and clears the ACK bit in the I²C Status Register. Software responds to the
Not Acknowledge interrupt by setting the stop and flush bits and clearing the TXI bit.
The I²C Controller sends the stop condition on the bus and clears the stop and NCKI
bits. The transaction is complete (ignore following steps).
12. The I²C Controller loads the I²C Shift Register with the contents of the I²C Data Reg-
ister (2nd byte of address).
13. The I²C Controller shifts the second address byte out the SDA signal. After the first
bit has been sent, the transmit interrupt is asserted.
14. Software responds by setting the stop bit in the I²C Control Register. The TXI bit can
be cleared at the same time.
15. Software polls the stop bit of the I²C Control Register. Hardware deasserts the stop bit
when the transaction is completed (stop condition has been sent).
16. Software checks the ACK bit of the I²C Status Register. If the slave acknowledged,
the ACK bit is = 1. If the slave does not acknowledge, the ACK bit is = 0. The NCKI
interrupt do not occur because the stop bit was set.
Write Transaction with a 10-Bit Address
Figure 31 displays the data transfer format for a 10-bit addressed slave. 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/S
Figure 31. 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
read/write control bit (=0). The transmit operation is carried out in the same manner as 7-
bit addressing.
Observe the following procedure for a transmit operation on a 10-bit addressed slave:
1. Software asserts the IEN bit in the I²C Control Register.
PS019924-0113
PRELIMINARY
Operation