45.6.3.6.1 7-bit Client Addressing

When addressing 7-bit client devices, the internal address bytes are used to perform random address (read or write) accesses to reach one or more data bytes, e.g. within a memory page location in a serial memory. When performing read operations with an internal address, the TWIHS performs a write operation to set the internal address into the client device, and then switch to Host Receiver mode. Note that the second START condition (after sending the IADR) is sometimes called “repeated start” (Sr) in I2C fully-compatible devices. See Host Read with One-, Two- or Three-Byte Internal Address and One Data Byte.

See Host Write with One-, Two- or Three-Byte Internal Address and One Data Byte and Internal Address Usage for the host write operation with internal address.

The three internal address bytes are configurable through TWIHS_MMR.

If the client device supports only a 7-bit address, i.e., no internal address, IADRSZ must be set to 0.

The table below shows the abbreviations used in the figures below.

Table 45-4. Abbreviations
Abbreviation Definition
S Start
Sr Repeated Start
P Stop
W Write
R Read
A Acknowledge
NA Not Acknowledge
DADR Device Address
IADR Internal Address
Figure 45-10. Host Write with One-, Two- or Three-Byte Internal Address and One Data Byte
Figure 45-11. Host Read with One-, Two- or Three-Byte Internal Address and One Data Byte