TIC12400-Q1: TIC12400 MSDI configuration as Analog input

Hello,

Yes, it is possible to use the ADC for all 24 inputs. For reference, see 8.2 "Functional Block Diagram" and section 8.3.8.2 Input Mode Selection, "Each input of the TIC12400-Q1 can be individually programmed to use either a comparator or an ADC by configuring the appropriate bits in the MODE register depending on the knowledge of the external switch connections."

The maximum voltage that can be applied can be seen in in "6.3 Recommended Operating Conditions", where VINX IN0 to IN23 input voltage has a max input voltage of 35V. However, it should be noted that the ADC full-scale range is 0 V to 6 V.

The “wake-up” feature is considered normal operation can be configured to assert the interrupt pin when it detects a state change. For example, if an input changes state, then the MCU would see this and read the status registers to see which input had a state change.

Regards, Amy

Hello Amy,

Thanks for your reply, I have some questions w.r.t ADC threshold.

below are my requirements.

Logic low* in digital mode 3.5 V

Logic high* in digital mode 7.7V

Max voltage 28V

Wetting current 10mA

Considering the above requirements, I will design a Voltage divider before the input pin such that when my Analog Voltage is 3.5V , voltage on the INX pin will be 2.5V and when

the voltage 7.7V , voltage on the INX will be 5V. whether the MSDI will be able to wake up by setting a threshold when the voltage on INX pin is >=5V and transfer the digital bits to MCU through SPI.

When the Voltage <=3.5V on INX pin of MSDI by setting a low threshold , is it possible to put the MSDI to pooling mode.

Unfortunately I was not able to post the image

Hello Amy,

Thanks for the quick reply,

I need to understand more about threshold setting

Inputs IN12 to IN17 use 2 preset threshold levels (THRES2A and THRES2B).- what is voltage Value that indicates those two registers.

THRES2A = _ V?
THRES2B = _ V?

Similarly whats is the Voltage value that indicates other registers.

THRES3A, = _ V?
THRES3B,= _ V?

THRES3C= _ V?

If these information  is available in the data sheet , kindly request you to provide the details.

If possible Please  can you provide me your email ID so that I can send a mail directly.

Hello Amy,

THRES_CFG1 to THRES_CFG2 are two registers used for Input IN0 to IN11. But for inputs IN12
to IN17 use 2 preset threshold levels (THRES2A and THRES2B) and similarly other Inputs IN13 to IN23 use present threshold.

So what will be the value(voltage) of Preset threshold for other inputs from IN12 to IN23.

Hello Amy ,

Thanks for your solution , I do understand the register setting and mapping based on your suggestions.

I have a confusion on ADC Voltage to the input pin.Please refer a below attachment of data sheet block diagram.

referring to the marked part of diagram, I can see an Voltage divider R1 and R2 integrated to the chip , based on this I have few questions.

does this Voltage divider internally scale down my input voltage on INX pin to 6V and give it to ADC block or do I need to scale down my voltage to 6V at the input by resistor divider ? if it is not , what is the purpose of these resistors and what is the value of this resistors?

Hello Amy,

according to Voltage divider ratio, VINX voltage will be divided by a factor of 3, Please refer the below calculations based on my assumption.

If my assumptions are wrong, please provide the correct calculations.wihich will speed up our design.  

Hi Darshan,

Thank you for sharing this. Based on lab measurements, this resistive divider is in the range of 120k = R1 = R2, equating to a divide by 2 ratio as shown in the datasheet. Hope this helps clarify.

Regards, Amy