Error in Energia Documentation? Current source/sink

[igor 163]

In at least two places the Energia documentation claims that LaunchPad pins can source or sink up to 40 mA.

 

Is that true of all (or any) of the launchpads supported by Energia?

(i.e., Stellaris/Tiva, Tiva Connected, MSP430, Fraunchpad, C2000, CC3200)

 

For the Stellaris launchpad, the documentation for the LM4F120 gives drive strength options of 2, 4, or 8 mA, and says up to 4 pins can sink 18 mA.  So where does the 40mA come from (or go to)?

 

Yet energia.nu says: "LaunchPad pins can source (provide positive current) or sink (provide negative current) up to 40 mA (milliamps) of current to other devices/circuits."

 

http://energia.nu/guide/tutorial_digitalpins/

http://energia.nu/reference/constants/

 

I note that the Arduino documentation says the same 40mA, so suspect this specification may have accidentally been copied from the AVR.  If so, seems like an invitation to release the magic smoke.

 

Please someone either point me to where the documentation says that the various launchpads can source/sink that much, or fix the web site to either include the actual numbers for the various launchpads, or remove the misleading number.

 

I previously posted this question on stellarisiti (where it failed to generate any action), but just noticed that the web site says to post documentation corrections on the 43oh Energia forums.

[spirilis 1,265]

That sounds like an oversight/error (paging @@energia )

[FredrikNyman 3]

You're right, this is looks like a documentation error.  How much each pin can source/sink is device dependent.  For the MSP430G2553, for example, under "Outputs, Ports Px" on page 24 in the datasheet, it specifies 6 mA per pin max (both for source and sink) and a maximum of 48 mA combined to hold the maximum voltage drop specified.

 

 

 

In at least two places the Energia documentation claims that LaunchPad pins can source or sink up to 40 mA.

 

Is that true of all (or any) of the launchpads supported by Energia?

(i.e., Stellaris/Tiva, Tiva Connected, MSP430, Fraunchpad, C2000, CC3200)

 

For the Stellaris launchpad, the documentation for the LM4F120 gives drive strength options of 2, 4, or 8 mA, and says up to 4 pins can sink 18 mA.  So where does the 40mA come from (or go to)?

 

Yet energia.nu says: "LaunchPad pins can source (provide positive current) or sink (provide negative current) up to 40 mA (milliamps) of current to other devices/circuits."

 

http://energia.nu/guide/tutorial_digitalpins/

http://energia.nu/reference/constants/

 

I note that the Arduino documentation says the same 40mA, so suspect this specification may have accidentally been copied from the AVR.  If so, seems like an invitation to release the magic smoke.

 

Please someone either point me to where the documentation says that the various launchpads can source/sink that much, or fix the web site to either include the actual numbers for the various launchpads, or remove the misleading number.

 

I previously posted this question on stellarisiti (where it failed to generate any action), but just noticed that the web site says to post documentation corrections on the 43oh Energia forums.

 

[roadrunner84 466]

Probably ports can sing up to 40mA. This is a shared ceiling for all pins on that port. So when sinking 8mA on 5 pins, the other 3 pins on that port cannot sink any more current.

At least, this seems to be the case for some MSP430s...