IC has pull-down resistors on SMBus lines?
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The datasheet of TI bq40z50-R2 (Li-Ion Battery Pack Manager) tells that "The SMBus clock and data lines have internal pulldown".
Pin equivalent Diagram is in image below:
Aren't usually the SMBus Data and Clock lines to be connected to pull-up resistors?
I'd like to connect this IC and a Battery Charger IC to same SMBus, but the latter requires pull-up resistors for the SMBus lines.
Would this work anyway?
Thanks
i2c smbus
asked 1 hour ago
haku15haku15
726
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add a comment |
$begingroup$
The datasheet of TI bq40z50-R2 (Li-Ion Battery Pack Manager) tells that "The SMBus clock and data lines have internal pulldown".
Pin equivalent Diagram is in image below:
Aren't usually the SMBus Data and Clock lines to be connected to pull-up resistors?
I'd like to connect this IC and a Battery Charger IC to same SMBus, but the latter requires pull-up resistors for the SMBus lines.
Would this work anyway?
Thanks
i2c smbus
asked 1 hour ago
haku15haku15
726
$endgroup$
add a comment |
$begingroup$
The datasheet of TI bq40z50-R2 (Li-Ion Battery Pack Manager) tells that "The SMBus clock and data lines have internal pulldown".
Pin equivalent Diagram is in image below:
Aren't usually the SMBus Data and Clock lines to be connected to pull-up resistors?
I'd like to connect this IC and a Battery Charger IC to same SMBus, but the latter requires pull-up resistors for the SMBus lines.
Would this work anyway?
Thanks
i2c smbus
asked 1 hour ago
haku15haku15
726
$endgroup$
The datasheet of TI bq40z50-R2 (Li-Ion Battery Pack Manager) tells that "The SMBus clock and data lines have internal pulldown".
Pin equivalent Diagram is in image below:
Aren't usually the SMBus Data and Clock lines to be connected to pull-up resistors?
I'd like to connect this IC and a Battery Charger IC to same SMBus, but the latter requires pull-up resistors for the SMBus lines.
Would this work anyway?
Thanks
i2c smbus
i2c smbus
asked 1 hour ago
haku15haku15
726
asked 1 hour ago
haku15haku15
726
asked 1 hour ago
haku15haku15
726
asked 1 hour ago
haku15haku15
726
asked 1 hour ago
haku15haku15
726
726
add a comment |
add a comment |
1 Answer
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The internal pull-downs in question are very weak, 1 MΩ. They are not meant to be "operational", and won't have any effect on normal I2C data transactions when the standard (10k-5k or 2k) pull-ups are attached to the I2C system bus. The reason for weak pull-downs is to provide well-defined bus state during power-on transients, when not all parts of the system are yet powered up.
The initial state with pull-downs is used by internal logic of the IC, per datasheet P.34:
When the gas gauge senses that both lines are low (such as during
removal of the pack),the device performs auto-offset calibration and
then goes into SLEEP mode to conserve power"
answered 1 hour ago
Ale..chenskiAle..chenski
28.9k11866
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$begingroup$
Just a tip: you can use HTML symbols in the posts.Ω,μ,°, etc. For superscripts and subscripts use HTML<sup>...</sup>and<sub>...</sub>. They don't work in the comments.
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– Transistor
1 hour ago
$begingroup$
Ok, thanks for the explanation!
$endgroup$
– haku15
22 mins ago
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@Transistor, thanks, and don't delete your comment - I will use it as future guide:-)
$endgroup$
– Ale..chenski
16 mins ago
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
$begingroup$
The internal pull-downs in question are very weak, 1 MΩ. They are not meant to be "operational", and won't have any effect on normal I2C data transactions when the standard (10k-5k or 2k) pull-ups are attached to the I2C system bus. The reason for weak pull-downs is to provide well-defined bus state during power-on transients, when not all parts of the system are yet powered up.
The initial state with pull-downs is used by internal logic of the IC, per datasheet P.34:
When the gas gauge senses that both lines are low (such as during
removal of the pack),the device performs auto-offset calibration and
then goes into SLEEP mode to conserve power"
answered 1 hour ago
Ale..chenskiAle..chenski
28.9k11866
$endgroup$
$begingroup$
Just a tip: you can use HTML symbols in the posts.Ω,μ,°, etc. For superscripts and subscripts use HTML<sup>...</sup>and<sub>...</sub>. They don't work in the comments.
$endgroup$
– Transistor
1 hour ago
$begingroup$
Ok, thanks for the explanation!
$endgroup$
– haku15
22 mins ago
$begingroup$
@Transistor, thanks, and don't delete your comment - I will use it as future guide:-)
$endgroup$
– Ale..chenski
16 mins ago
add a comment |
$begingroup$
The internal pull-downs in question are very weak, 1 MΩ. They are not meant to be "operational", and won't have any effect on normal I2C data transactions when the standard (10k-5k or 2k) pull-ups are attached to the I2C system bus. The reason for weak pull-downs is to provide well-defined bus state during power-on transients, when not all parts of the system are yet powered up.
The initial state with pull-downs is used by internal logic of the IC, per datasheet P.34:
When the gas gauge senses that both lines are low (such as during
removal of the pack),the device performs auto-offset calibration and
then goes into SLEEP mode to conserve power"
answered 1 hour ago
Ale..chenskiAle..chenski
28.9k11866
$endgroup$
$begingroup$
Just a tip: you can use HTML symbols in the posts.Ω,μ,°, etc. For superscripts and subscripts use HTML<sup>...</sup>and<sub>...</sub>. They don't work in the comments.
$endgroup$
– Transistor
1 hour ago
$begingroup$
Ok, thanks for the explanation!
$endgroup$
– haku15
22 mins ago
$begingroup$
@Transistor, thanks, and don't delete your comment - I will use it as future guide:-)
$endgroup$
– Ale..chenski
16 mins ago
add a comment |
$begingroup$
The internal pull-downs in question are very weak, 1 MΩ. They are not meant to be "operational", and won't have any effect on normal I2C data transactions when the standard (10k-5k or 2k) pull-ups are attached to the I2C system bus. The reason for weak pull-downs is to provide well-defined bus state during power-on transients, when not all parts of the system are yet powered up.
The initial state with pull-downs is used by internal logic of the IC, per datasheet P.34:
When the gas gauge senses that both lines are low (such as during
removal of the pack),the device performs auto-offset calibration and
then goes into SLEEP mode to conserve power"
answered 1 hour ago
Ale..chenskiAle..chenski
28.9k11866
$endgroup$
The internal pull-downs in question are very weak, 1 MΩ. They are not meant to be "operational", and won't have any effect on normal I2C data transactions when the standard (10k-5k or 2k) pull-ups are attached to the I2C system bus. The reason for weak pull-downs is to provide well-defined bus state during power-on transients, when not all parts of the system are yet powered up.
The initial state with pull-downs is used by internal logic of the IC, per datasheet P.34:
When the gas gauge senses that both lines are low (such as during
removal of the pack),the device performs auto-offset calibration and
then goes into SLEEP mode to conserve power"
answered 1 hour ago
Ale..chenskiAle..chenski
28.9k11866
edited 1 hour ago
answered 1 hour ago
Ale..chenskiAle..chenski
28.9k11866
answered 1 hour ago
Ale..chenskiAle..chenski
28.9k11866
answered 1 hour ago
Ale..chenskiAle..chenski
28.9k11866
28.9k11866
$begingroup$
Just a tip: you can use HTML symbols in the posts.Ω,μ,°, etc. For superscripts and subscripts use HTML<sup>...</sup>and<sub>...</sub>. They don't work in the comments.
$endgroup$
– Transistor
1 hour ago
$begingroup$
Ok, thanks for the explanation!
$endgroup$
– haku15
22 mins ago
$begingroup$
@Transistor, thanks, and don't delete your comment - I will use it as future guide:-)
$endgroup$
– Ale..chenski
16 mins ago
add a comment |
$begingroup$
Just a tip: you can use HTML symbols in the posts.Ω,μ,°, etc. For superscripts and subscripts use HTML<sup>...</sup>and<sub>...</sub>. They don't work in the comments.
$endgroup$
– Transistor
1 hour ago
$begingroup$
Ok, thanks for the explanation!
$endgroup$
– haku15
22 mins ago
$begingroup$
@Transistor, thanks, and don't delete your comment - I will use it as future guide:-)
$endgroup$
– Ale..chenski
16 mins ago
$begingroup$
Just a tip: you can use HTML symbols in the posts.
Ω, μ, °, etc. For superscripts and subscripts use HTML <sup>...</sup> and <sub>...</sub>. They don't work in the comments.$endgroup$
– Transistor
1 hour ago
$begingroup$
Just a tip: you can use HTML symbols in the posts.
Ω, μ, °, etc. For superscripts and subscripts use HTML <sup>...</sup> and <sub>...</sub>. They don't work in the comments.$endgroup$
– Transistor
1 hour ago
$begingroup$
Ok, thanks for the explanation!
$endgroup$
– haku15
22 mins ago
$begingroup$
Ok, thanks for the explanation!
$endgroup$
– haku15
22 mins ago
$begingroup$
@Transistor, thanks, and don't delete your comment - I will use it as future guide:-)
$endgroup$
– Ale..chenski
16 mins ago
$begingroup$
@Transistor, thanks, and don't delete your comment - I will use it as future guide:-)
$endgroup$
– Ale..chenski
16 mins ago
add a comment |
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