Datasheet

Chapter 11 Inter-Integrated Circuit (S08IICV2)
MC9S08DN60 Series Data Sheet, Rev 3
Freescale Semiconductor 207
11.4.2 10-bit Address
For 10-bit addressing, 0x11110 is used for the first 5 bits of the first address byte. Various combinations of
read/write formats are possible within a transfer that includes 10-bit addressing.
11.4.2.1 Master-Transmitter Addresses a Slave-Receiver
The transfer direction is not changed (see Table 11-9). When a 10-bit address follows a start condition,
each slave compares the first seven bits of the first byte of the slave address (11110XX) with its own
address and tests whether the eighth bit (R/
W direction bit) is 0. More than one device can find a match
and generate an acknowledge (A1). Then, each slave that finds a match compares the eight bits of the
second byte of the slave address with its own address. Only one slave finds a match and generates an
acknowledge (A2). The matching slave remains addressed by the master until it receives a stop condition
(P) or a repeated start condition (Sr) followed by a different slave address.
After the master-transmitter has sent the first byte of the 10-bit address, the slave-receiver sees an IIC
interrupt. Software must ensure the contents of IICD are ignored and not treated as valid data for this
interrupt.
11.4.2.2 Master-Receiver Addresses a Slave-Transmitter
The transfer direction is changed after the second R/W bit (see Table 11-10). Up to and including
acknowledge bit A2, the procedure is the same as that described for a master-transmitter addressing a
slave-receiver. After the repeated start condition (Sr), a matching slave remembers that it was addressed
before. This slave then checks whether the first seven bits of the first byte of the slave address following
Sr are the same as they were after the start condition (S) and tests whether the eighth (R/
W) bit is 1. If there
is a match, the slave considers that it has been addressed as a transmitter and generates acknowledge A3.
The slave-transmitter remains addressed until it receives a stop condition (P) or a repeated start condition
(Sr) followed by a different slave address.
After a repeated start condition (Sr), all other slave devices also compare the first seven bits of the first byte
of the slave address with their own addresses and test the eighth (R/
W) bit. However, none of them are
addressed because R/
W = 1 (for 10-bit devices) or the 11110XX slave address (for 7-bit devices) does not
match.
After the master-receiver has sent the first byte of the 10-bit address, the slave-transmitter sees an IIC
interrupt. Software must ensure the contents of IICD are ignored and not treated as valid data for this
interrupt.
S
Slave Address 1st 7 bits R/W
A1
Slave Address 2nd byte
A2 Data A ... Data A/A P
11110 + AD10 + AD9 0 AD[8:1]
Table 11-9. Master-Transmitter Addresses Slave-Receiver with a 10-bit Address
S
Slave Address
1st 7 bits
R/W
A1
Slave Address
2nd byte
A2 Sr
Slave Address
1st 7 bits
R/W
A3 Data A ... Data A P
11110 + AD10 + AD9 0 AD[8:1] 11110 + AD10 + AD9 1
Table 11-10. Master-Receiver Addresses a Slave-Transmitter with a 10-bit Address