Linux/BQ27426: Documentation question on how to set GPOUT pin and its polarity bit

Tool/software: Linux

Just added e-mail chain here,  

Eric,

Let’s assume SOC < SOC1 is the active state, then we want the GPOUT pin to be in the active state , as defined by the polarity bit.

So if the polarity bit is set high then GPOUT should be high, if polarity is set low then GPOUT should be low.

 V200t_Fuel_Gauge_GPOUT.docx

Does this make sense?

Michael

From: Szyper, Eric [mailto:e-szyper1@ti.com]
Sent: Tuesday, July 18, 2017 2:57 PM
To: Jack Grenfell; Maxwell, David; Hartl, Dominik
Cc: Michael Schmid; Sebastian Nedumala
Subject: RE: Request for information -- BQ27426.

Jack,

I have to agree with you… those statements do seem to contradict one another.  Can you confirm which behavior you “want”?   If SOC < SOC1 SET THRESHOLD…  do you want GPOUT to be “HIGH” or “LOW”?

David, I know Dominik is out of office…   can you please take a look at this, and confirm the correct relationship between GPIOPOL, and GPOUT?   If the statement is incorrect in the datasheet, can we also please get that corrected?  

Thank you.

Best regards,

Eric Szyper
Texas Instruments
Field Sales & Applications
916-749-0741
e-szyper1@ti.com

From: Jack Grenfell [mailto:Jack_G1@VERIFONE.com]
Sent: Friday, July 14, 2017 3:45 PM
To: Maxwell, David; Hartl, Dominik; Szyper, Eric
Cc: Michael Schmid; Sebastian Nedumala
Subject: RE: Request for information -- BQ27426.

All,

I just added another sentence regarding GPOUT that seems to conflict with the first statement.  It is highlighted in Yellow below.

-jack

From: Jack Grenfell
Sent: Friday, July 14, 2017 3:36 PM
To: David Maxwell (dmaxwell@ti.com); Hartl, Dominik (d-hartl@ti.com); e-szyper1@ti.com
Cc: Michael Schmid; Sebastian Nedumala
Subject: Request for information -- BQ27426.

David, Dominik, Eric,

We want to make sure we understand this paragraph in the BQ27426 TRM;

When the BAT_LOW function is activated, the signaling on the multiplexed pin follows the status of the

[SOC1] bit in the Flags() register. The fuel gauge has two flags accessed by the Flags() function that

warns when the battery SOC has fallen to critical levels. When StateOfCharge() falls below the first

capacity threshold, specified in SOC1 Set Threshold, the [SOC1] flag is set. The flag is cleared once

StateOfCharge() rises above SOC1 Set Threshold. The GPOUT pin automatically reflects the status of

the [SOC1] flag when [BATLOWEN] = 1 and [GPIOPOL] = 0. The polarity can be flipped by setting

[GPIOPOL] = 1.

GPIOPOL = GPOUT pin is active-high if set or active-low if cleared.

In the command below, we believe we are setting the GPIOPOL to a 1.

W: aa 3e 40 00                                                                                                  
bqtool: bqfs_get_cmd(): >>                                                                                      
W: aa 40 6c 7c 0f 9f 23 00 00 14 04 00 09 04 26 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  

Here is the Schematic for Reference…

Please review the attached document and comment.

Regards,

Jack Grenfell

Hardware System Architect

1-916-625-1842

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