RM0367 Rev 7 735/1043
RM0367 Inter-integrated circuit (I2C) interface
763
Caution: Changing the TIMEOUTA and TIDLE configuration is not allowed when the TIMEOUTEN is
set.
28.4.14 SMBus: I2C_TIMEOUTR register configuration examples
This section is relevant only when SMBus feature is supported. Refer to Section 28.3: I2C
implementation.
• Configuring the maximum duration of t
TIMEOUT
to 25 ms:
• Configuring the maximum duration of t
LOW:SEXT
and t
LOW:MEXT
to 8 ms:
• Configuring the maximum duration of t
IDLE
to 50 µs
28.4.15 SMBus slave mode
This section is relevant only when the SMBus feature is supported. Refer to Section 28.3:
I2C implementation.
In addition to I2C slave transfer management (refer to Section 28.4.9: I2C slave mode)
some additional software flowcharts are provided to support the SMBus.
SMBus slave transmitter
When the IP is used in SMBus, SBC must be programmed to ‘1’ in order to allow the PEC
transmission at the end of the programmed number of data bytes. When the PECBYTE bit
is set, the number of bytes programmed in NBYTES[7:0] includes the PEC transmission. In
Table 133. Examples of TIMEOUTA settings for various I2CCLK
frequencies
(max t
TIMEOUT
= 25 ms)
f
I2CCLK
TIMEOUTA[11:0] bits TIDLE bit TIMEOUTEN bit t
TIMEOUT
8 MHz 0x61 0 1 98 x 2048 x 125 ns = 25 ms
16 MHz 0xC3 0 1 196 x 2048 x 62.5 ns = 25 ms
32 MHz 0x186 0 1 391 x 2048 x 31.25 ns = 25 ms
Table 134. Examples of TIMEOUTB settings for various I2CCLK frequencies
f
I2CCLK
TIMEOUTB[11:0] bits TEXTEN bit t
LOW:EXT
8 MHz 0x1F 1 32 x 2048 x 125 ns = 8 ms
16 MHz 0x3F 1 64 x 2048 x 62.5 ns = 8 ms
32 MHz 0x7C 1 125 x 2048 x 31.25 ns = 8 ms
Table 135. Examples of TIMEOUTA settings for various I2CCLK frequencies
(max t
IDLE
= 50 µs)
f
I2CCLK
TIMEOUTA[11:0] bits TIDLE bit TIMEOUTEN bit t
TIDLE
8 MHz 0x63 1 1 100 x 4 x 125 ns = 50 µs
16 MHz 0xC7 1 1 200 x 4 x 62.5 ns = 50 µs
32 MHz 0x18F 1 1 400 x 4 x 31.25 ns = 50 µs
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