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i2c bus hangs in master RPi access to MSP430G uC ~1 in 1000 accesses

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... resetting the MSP430 clears the hung state. I've slowed down the i2c clock freq, beefed up the PSupply, changed pull-up resistors - no change. However I made the "errors" increase significantly by busying the ARM with 2 calculation-intensive programs. I use Python in RPi, using smbus, SMBUS and
i2c_LCD_driver and try/except routines in the RPi to catch the bad access and reset the MSP - after that, accesses every 5 seconds continue fine until the next hang, ~1000 accesses later. I use C for the ISRs to manage interrupts in the MSP430.

I know both devices have hardware state machines that manage the i2c. Given that I can hang the bus by overworking the RPi, my suspicion was/is the implementation of the canned i2c python code. Is anyone aware of any weird
stuff about the Broadcom Serial Controller (BSC) i2c controller in the ARM that would hang a slave's state machine based on busy-ness of the OS managing the BSC ... or other cases of very intermittent bus hangs ?

i2c

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3

1

... resetting the MSP430 clears the hung state. I've slowed down the i2c clock freq, beefed up the PSupply, changed pull-up resistors - no change. However I made the "errors" increase significantly by busying the ARM with 2 calculation-intensive programs. I use Python in RPi, using smbus, SMBUS and
i2c_LCD_driver and try/except routines in the RPi to catch the bad access and reset the MSP - after that, accesses every 5 seconds continue fine until the next hang, ~1000 accesses later. I use C for the ISRs to manage interrupts in the MSP430.

I know both devices have hardware state machines that manage the i2c. Given that I can hang the bus by overworking the RPi, my suspicion was/is the implementation of the canned i2c python code. Is anyone aware of any weird
stuff about the Broadcom Serial Controller (BSC) i2c controller in the ARM that would hang a slave's state machine based on busy-ness of the OS managing the BSC ... or other cases of very intermittent bus hangs ?

i2c

share

asked 2 hours ago

JoeMJoeM

161

New contributor

JoeM is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

add a comment | 

... resetting the MSP430 clears the hung state. I've slowed down the i2c clock freq, beefed up the PSupply, changed pull-up resistors - no change. However I made the "errors" increase significantly by busying the ARM with 2 calculation-intensive programs. I use Python in RPi, using smbus, SMBUS and
i2c_LCD_driver and try/except routines in the RPi to catch the bad access and reset the MSP - after that, accesses every 5 seconds continue fine until the next hang, ~1000 accesses later. I use C for the ISRs to manage interrupts in the MSP430.

I know both devices have hardware state machines that manage the i2c. Given that I can hang the bus by overworking the RPi, my suspicion was/is the implementation of the canned i2c python code. Is anyone aware of any weird
stuff about the Broadcom Serial Controller (BSC) i2c controller in the ARM that would hang a slave's state machine based on busy-ness of the OS managing the BSC ... or other cases of very intermittent bus hangs ?

i2c

share

asked 2 hours ago

JoeMJoeM

161

New contributor

JoeM is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share

asked 2 hours ago

JoeMJoeM

161

New contributor

JoeM is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

share

asked 2 hours ago

JoeMJoeM

161

New contributor

JoeM is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 2 hours ago

JoeMJoeM

161

New contributor

JoeM is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.

asked 2 hours ago

JoeMJoeM

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Question

... I've slowed down the i2c clock freq ...

Answer

I am using RPi3B+ stretch 2019apr python 3.5.3.

I surprisingly and sadly experienced, and read that Rpi3B+ stretch python 3.5x I2C is buggy.

I could never have slowed down the default I2C 100kHz. I tried to change speed up to 400kHz and down to 50kHz. But hardware did not respond - no nothing changed. :(

I read that it is a hardware bug. Are you sure you have actually successfully changed the speed? I vaguely remember that I could indeed change the speed when I was in jessie or earlier days.

I also found that python 3.5.3 block read does not fully implement to entertain all the parameter patterns. My projects were "hung" and much time wasted. :(

I am anxiously waiting for the coming soon Rpi4 to hopefully resume my couple of long stalled I2C related projects. In the meaning time I am switching to SPI (I2C MCP23017 to SPI MCP23S17, etc)

Update 2019apr21hkt1156

I did try smbus2 but sadly encountered other compatibility problems. :(

References

Rpi3 I2C Baud Rate Setting - samtal 2018aug04

/ to continue, ...

share|improve this answer

edited 9 mins ago

answered 1 hour ago

tlfong01tlfong01

832312

add a comment | 

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1

Question

... I've slowed down the i2c clock freq ...

Answer

I am using RPi3B+ stretch 2019apr python 3.5.3.

I surprisingly and sadly experienced, and read that Rpi3B+ stretch python 3.5x I2C is buggy.

I could never have slowed down the default I2C 100kHz. I tried to change speed up to 400kHz and down to 50kHz. But hardware did not respond - no nothing changed. :(

I read that it is a hardware bug. Are you sure you have actually successfully changed the speed? I vaguely remember that I could indeed change the speed when I was in jessie or earlier days.

I also found that python 3.5.3 block read does not fully implement to entertain all the parameter patterns. My projects were "hung" and much time wasted. :(

I am anxiously waiting for the coming soon Rpi4 to hopefully resume my couple of long stalled I2C related projects. In the meaning time I am switching to SPI (I2C MCP23017 to SPI MCP23S17, etc)

Update 2019apr21hkt1156

I did try smbus2 but sadly encountered other compatibility problems. :(

References

Rpi3 I2C Baud Rate Setting - samtal 2018aug04

/ to continue, ...

share|improve this answer

edited 9 mins ago

answered 1 hour ago

tlfong01tlfong01

832312

add a comment | 

1

Question

... I've slowed down the i2c clock freq ...

Answer

I am using RPi3B+ stretch 2019apr python 3.5.3.

I surprisingly and sadly experienced, and read that Rpi3B+ stretch python 3.5x I2C is buggy.

I could never have slowed down the default I2C 100kHz. I tried to change speed up to 400kHz and down to 50kHz. But hardware did not respond - no nothing changed. :(

I read that it is a hardware bug. Are you sure you have actually successfully changed the speed? I vaguely remember that I could indeed change the speed when I was in jessie or earlier days.

I also found that python 3.5.3 block read does not fully implement to entertain all the parameter patterns. My projects were "hung" and much time wasted. :(

I am anxiously waiting for the coming soon Rpi4 to hopefully resume my couple of long stalled I2C related projects. In the meaning time I am switching to SPI (I2C MCP23017 to SPI MCP23S17, etc)

Update 2019apr21hkt1156

I did try smbus2 but sadly encountered other compatibility problems. :(

References

Rpi3 I2C Baud Rate Setting - samtal 2018aug04

/ to continue, ...

share|improve this answer

edited 9 mins ago

answered 1 hour ago

tlfong01tlfong01

832312

add a comment | 

Question

... I've slowed down the i2c clock freq ...

Answer

I am using RPi3B+ stretch 2019apr python 3.5.3.

I surprisingly and sadly experienced, and read that Rpi3B+ stretch python 3.5x I2C is buggy.

I could never have slowed down the default I2C 100kHz. I tried to change speed up to 400kHz and down to 50kHz. But hardware did not respond - no nothing changed. :(

I read that it is a hardware bug. Are you sure you have actually successfully changed the speed? I vaguely remember that I could indeed change the speed when I was in jessie or earlier days.

I also found that python 3.5.3 block read does not fully implement to entertain all the parameter patterns. My projects were "hung" and much time wasted. :(

I am anxiously waiting for the coming soon Rpi4 to hopefully resume my couple of long stalled I2C related projects. In the meaning time I am switching to SPI (I2C MCP23017 to SPI MCP23S17, etc)

Update 2019apr21hkt1156

I did try smbus2 but sadly encountered other compatibility problems. :(

References

Rpi3 I2C Baud Rate Setting - samtal 2018aug04

/ to continue, ...

share|improve this answer

edited 9 mins ago

answered 1 hour ago

tlfong01tlfong01

832312

share|improve this answer

edited 9 mins ago

answered 1 hour ago

tlfong01tlfong01

832312

answered 1 hour ago

tlfong01tlfong01

832312

answered 1 hour ago

tlfong01tlfong01

832312