Tool/software:
Hi all,
I recognized that TSRef has no register to read out in the BQ79718. I’m wondering a little bit, because it will used for Ratio metric. So if I would work with TSRef voltage, youhave to connect it to a GPIO, isn’t it?
In the Safety Manuel of BQ7961x SM142 MAIN ADC TSREF Diagnostic we have to measure TSRef. A comparable SM doesn’t exist in BQ79718. Both have still the standard SM for OV/UV/OC of TSRef-Pin
With BQ79718 you have to measure the temperature with ratio metric.
Safety Measures for GPIO Diagnostic needs to measure an absolute voltage.
This Safety measures need a reference absolute for their diagnostic. To configure the GPIO to absolute for the reference needs time.
- SM_GPIO_OPNWR: GPIO Open Wire Detection (FDTI à PPE41 project every 100ms)
- SM_GPIO_ADJSHRT: GPIO Adjacent Short Diagnostic (FDTI à PPE41 project every 100ms)
GPIO Configuration
|
0b000 = As disabled, high-Z. |
n.a. |
|
0b001 = As ADC and OTUT inputs (ratio metric). |
Temperature Measurement Option Reference and Measurement with multiplication of TSRef (Not Measured à 4V):
|
|
0b010 = As ADC only input (absolute). |
Reference and Measurement:
|
|
0b011 = As digital input. |
n.a. |
|
0b100 = As digital output high. |
Innervate SM_GPIO_ADJSHRT: GPIO Adjacent Short Diagnostic |
|
0b101 = As digital output low. |
Innervate SM_GPIO_ADJSHRT: GPIO Adjacent Short Diagnostic |
|
0b110 = As ADC input (absolute) and weak pull-up. |
Innervate SM_GPIO_OPNWR: GPIO Open Wire Detection |
|
0b111 = As ADC input (absolute) and weak pull-down. |
Innervate SM_GPIO_OPNWR: GPIO Open Wire Detection |
Are there any settling or waiting times in case we change GPIO configuration from ratio metric to absolute and vice versa?
When we would measure with a GPIO TSRef we could use ratio metric to evaluate GPIO voltage:
U_GPIO = ratio_GPIO * U_GPIO_TSREF
Is it recommended to multiply ratio metric value and TSRef voltage to get GPIO voltage?