EFM32WG Datasheet, PDF (414/834 Pages) List of Unclassifed Manufacturers – The EFM32WG Wonder Gecko is the ideal choice for demanding 8-, 16-, and 32-bit energy sensitive applications.

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on the bus can try to gain control of it. If the current master wishes to make another transfer immediately
after the current, it can start a new transfer directly by transmitting a repeated START condition (Sr)
instead of a STOP followed by a START.
Examples of I²C transfers are shown in Figure 16.5 (p. 414), Figure 16.6 (p. 414), and Figure 16.7 (p.
414) . The identifiers used are:
• ADDR - Address
• DATA - Data
• S - Start bit
• Sr - Repeated start bit
• P - Stop bit
• W/R - Read(1)/Write(0)
• A - ACK
• N - NACK
Figure 16.5. I²C Single Byte Write to Slave
S
ADDR
WA
DATA
AP
Figure 16.6. I²C Double Byte Read from Slave
S
ADDR
RA
DATA
A
DATA
NP
Figure 16.7. I²C Single Byte Write, then Repeated Start and Single Byte Read
S
ADDR
WA
DATA
A Sr
ADDR
RA
DATA
NP
16.3.1.3 Addresses
I²C supports both 7-bit and 10-bit addresses. When using 7-bit addresses, the first byte transmitted after
the START-condition contains the address of the slave that the master wants to contact. In the 7-bit
address space, several addresses are reserved. These addresses are summarized in Table 16.1 (p.
414) , and include a General Call address which can be used to broadcast a message to all slaves
on the I²C-bus.
Table 16.1. I²C Reserved I²C Addresses
I²C Address
R/W
Description
0000-000
0
General Call address
0000-000
1
START byte
0000-001
X
Reserved for the C-Bus format
0000-010
X
Reserved for a different bus format
0000-011
X
Reserved for future purposes
0000-1XX
X
Reserved for future purposes
1111-1XX
X
Reserved for future purposes
1111-0XX
X
10 Bit slave addressing mode
16.3.1.4 10-bit Addressing
To address a slave using a 10-bit address, two bytes are required to specify the address instead of
one. The seven first bits of the first byte must then be 1111 0XX, where XX are the two most significant
bits of the 10-bit address. As with 7-bit addresses, the eight bit of the first byte determines whether the
2013-05-08 - Wonder Gecko Family - d0233_Rev0.50
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