TMPM366FDFG/FYFG/FWFG
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TMPM366FDFG/FYFG/FWFG
Important Notices
Make sure to read read this chapter before using the product.
1 Serial bus interface
There are restrictions on the use of I2C bus mode when the multi-master function is used.
1.1
Description
When the multi-master function is used in I2C bus mode, if these masters start the communications simulta-
neously, the following phenomena may occur:
1. Communications may be locked up.
2. SCL pulse widths shorten; therefore these pulses may not satisfy I2C Specifications.
1.2
Condition
These phenomena occur only when the multi-master function is used in I2C bus mode. If a single master is
used, these phenomena do not occur.
1.3
Workaround
There is no workaround for these phenomena. Perform recovery process by software.
1.4
How to Recover from These Phenomena
Perform recovery process by software.
By using a timer, add timeout process to check whether communication is in a lock-up state.
An example of recovery process:
1. Start a timer count synchronously with start of the transmission.
2. If a serial interface interrupt (INTSBIx) does not occur in a certain period, the MCU determines the
timeout.
3. If the MCU determines the timeout, communications may be locked up. Perform software reset on the
serial bus interface circuit. This circuit is initialized to release communication from the lock up state.
4. Resend transmission data.
Mostly, Process 1 to 4 are enough to recovery; however if the multiple products are connected to the same
bus line, add a delay time between each product's recovery process before Process 4 (resending data) is per-
formed. This delay makes a time difference between each master; therefore bus collision can be avoided when
the data is sent again.
2015/1
stm32/stm8
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