Inter-integrated circuit (I2C) interface RM0367
732/1043 RM0367 Rev 7
Figure 235. Timeout intervals for t
LOW:SEXT
, t
LOW:MEXT
.
t
LOW:SEXT
(1)
Cumulative clock low extend time (slave device) - 25 ms
t
LOW:MEXT
(2)
Cumulative clock low extend time (master device) - 10 ms
1. t
LOW:SEXT
is the cumulative time a given slave device is allowed to extend the clock cycles in one message
from the initial START to the STOP. It is possible that, another slave device or the master also extends the
clock causing the combined clock low extend time to be greater than t
LOW:SEXT
. Therefore, this parameter is
measured with the slave device as the sole target of a full-speed master.
2. t
LOW:MEXT
is the cumulative time a master device is allowed to extend its clock cycles within each byte of a
message as defined from START-to-ACK, ACK-to-ACK, or ACK-to-STOP. It is possible that a slave device
or another master also extends the clock causing the combined clock low time to be greater than t
LOW:MEXT
on a given byte. Therefore, this parameter is measured with a full speed slave device as the sole target of
the master.
Table 131. SMBus timeout specifications (continued)
Symbol Parameter
Limits
Unit
Min Max
MS19866V1
Start Stop
t
LOW:SEXT
t
LOW:MEXT
t
LOW:MEXT
t
LOW:MEXT
Clk
Ack
Clk
Ack
SMBCLK
SMBDAT