SK-AM62: Understanding I2c driver calls in MCU+SDK 8.05 and modifying it adapt for FreeRTOS application

Hello

The driver you are pointing to you is a community driver that was done by Intel in 2016, it is not specifically tied to AM62. TI provides generic drivers for components that are on TI EVM. 

What you are asking for is more custom support, on Free RTOS. That is not something we can directly facilitate. If you implement this on your custom board and run into issue with the I2C drivers that come with the MCU+ SDK , we can try to provide some guidance. No plans to do any specific drivers for a specific customer/custom request.

Regards

Mukul 

Hi Mukul,

I understand your statements above, But since ADS-1015 is ADC chip from TI.

We need your help in identifying what bare minimum config needs to be done for registers from datasheet to start reading the data from I2c lines.

We will create the bare minimum skeleton driver based on Free rtos and No RTOS based APi's.

PFA the datasheet we are referring to as below

ADS101x-Q1.pdf

Thanks & Regards,

Pawamana Tanjore.

Hi Mukul,

since we are using multiple input channels we have few queries. below is our requirement

• select Config register using  Address pointer  register using  0x0001U  value , write it to I2c   for selecting  input as AIN3
• write 111 binary  in Config  register to select the AIN3 as input 
• Now again Select Conversion register using Address pointer register  using 0x0000U and write it to I2c
• So i have to do 2 writes back 2 back.
• PDF documentation i a m attaching below has some method, can you understand the logic to achieve it..?

Can you guide me by sharing some pseudo code for this logic..?

Thanks & Regards,

Pawamana Tanjore.

Hi Mukul,

Can you reply on the same..!

Pawamana,

can you please help me understand if your Hardware setup, just to ensure that there are no issues on HW front.

Also have you looked at the I2C Read Examples here https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/08_06_00_18/exports/docs/api_guide_am62x/EXAMPLES_DRIVERS_I2C_READ.html

The I2C Drivers for MCU domain is supported , please check it here at the buildsheet https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/08_06_00_18/exports/docs/build_sheet/am62x-sw-buildsheet.html

Regards

Anshu

Anshu Choudhary said:

Also have you looked at the I2C Read Examples here https://software-dl.ti.com/mcu-plus-sdk/esd/AM62X/08_06_00_18/exports/docs/api_guide_am62x/EXAMPLES_DRIVERS_I2C_READ.html

Yes Anshu, I have verified the sample code and started implementing with the same as reference.

2100.ADS101x-Q1.pdf

i am following section 9.1.7 Quickstart Guide of ADS-101x data sheet attached  above .

Below is the code and i want to select AIN3 as input to ADC chip ADS-1015

        /* found temperature sensor */
        /* Set configuration register to select AIN3 in 1015 */
        I2C_Transaction_init(&i2cTransaction);
        i2cTransaction.writeBuf   = txbuffer;
        i2cTransaction.writeCount = 3;
        i2cTransaction.slaveAddress = deviceAddress;
        txBuffer[0] = ADS101X_CONFIG_REG;
        txBuffer[1] = 0xF5; /*3rd byte is to select AIN3 input */
        txbuffer[2] = 0x83; /*4th byte is  selected as default */
        status = I2C_transfer(i2cHandle, &i2cTransaction);

Can you please suggest/ confirm whether this approach is correct way of writing to Config register to select AIN3 pin as input for ADC chip ADS-1015x..?

Please correct and provide some guidance of this is wrong method..?

Currently we don't have ADC chip on Board to verify the code result, Hence your guidance can help us a lot..

Thanks & Regards,

Pawamana Tanjore.

Hi  Anshu Choudhary/Mukul Bhatnagar,

Hope my ask is clear, please provide your answers for the same.

we are interested to have a one time short call for this topic to ask relevant queries.

BR's

Pawamana 

Pawamana,

I don't think we will be able to help you with custom driver development. I would also recommend to use the ADC ADS101x EVM for driver development. Using Logic analyzer(like saleae )for verifying the Initial Frame structure will also be helpful. I will also try to reach out to my colleague in ADC Team to see if they can help.

Regards

Anshu 

Hi Anshu,

I am able to make my low level application using sample example...!

However I need some inputs on this below highlighted comment from ADS-101x data sheet, Hopefully  i expect atleast for  below queries you can help us..!

8.6.2 Conversion Register (P[1:0] = 0h) [reset = 0000h]
The 16-bit Conversion register contains the result of the last conversion in binary two's complement format.
Following power-up, the Conversion register is cleared to 0, and remains 0 until the first conversion is completed

• why is the last conversion stored in 2's complement format..?
• Do we need to convert this 2's complement to normal binary
• What do we need to do in case of negative value, should we do sign extension
• please share some code snippets for the same please

BR's

Pawamana Tanjore.

Pawamana ,

these questions will be best answered by Experts in ADC Forum. These are ADC Centric Questions.

I am going to transfer the question to the appropriate business unit. Thanks for your patience.

Regards

Anshu

Hi Anshu,

I saw some documentation relevant to i2c programming recently from TI website.

Please find the screenshot of  the same, i downloaded the code.

This code mentioned in below link and screenshot  looks similar to one i tried implementing for ADS1015 ADC (NoRTOS + Free RTOS)

ADS1115 Example C Code Software

• can you have  a look of this and reply whether this is meant for sample code for FREERTOS+ NO RTOS(M4F) core..?
• If so why this link wasn't provided all these days..!
• If there are more links code snippets similar to this for ADC (ADS1015) interfacing  for different sensors, please share it.

Pawamana ,

I am glad you could find resources on ADS115 Product page. i am routing your query to the ADS Experts.

regards

Anshu