DS90UB954-Q1EVM: ALP: Read from 16bit register addresses

Michael Gilge

Part Number: DS90UB954-Q1EVM
Other Parts Discussed in Thread: ALP, , DS90UB953-Q1

Tool/software:

We are using the DS90UB954-Q1EVM and the ALP software. The EVM is connected to a camera with the DS90UB953-Q serializer.

I want to read registers of the camera via the ALP scripting. When I scab for connected devices, the slave address of the camera is listed.

The camera registers have 16bit addresses. The method of accessing 16bit addressed registers does not seem to work: The scope shows 8 bit to be send and the SDA line is kept low,

How do I access 16bit registers?

I tried board.ReadI2C(0x20, 0x00, [0x44]), but it does not seem to work.

over 1 year ago

0 Hamzeh Jaradat over 1 year ago

TI__Guru** 108650 points

Hello Michael,

can you provide more details?

What is the device address? And what is the register address?

Also, which value are you trying to write?

0 Michael Gilge over 1 year ago in reply to Hamzeh Jaradat

Expert 1720 points

Hello Hamzeh,

it is a camera sensor, which is connected via the DS90UB953-Q1. The device address is: 0x20 (8-bit)

We need to read registers like this one:

I tried with a scope and the serializer writes the device address followed by an 8-bit register address, not 16-bit.

The device keeps SDA low, waiting for the second address byte.

0 Hamzeh Jaradat over 1 year ago in reply to Michael Gilge

TI__Guru** 108650 points

Hello Michael,

can you try

board.ReadI2C(0x20, 0x00, [0x04, 0x01])

0 Michael Gilge over 1 year ago in reply to Hamzeh Jaradat

Expert 1720 points

I tried that as well but no change.

Can you check whether the ALP tool and the scripting will actually do 16bit addresses?

0 Hamzeh Jaradat over 1 year ago in reply to Michael Gilge

TI__Guru** 108650 points

Hi Michael,

yes, the ALP tool does support 16-bit and 32-bit addresses.

I have tested this example in the past and it worked for me:

The I2C address of the imager is 0xC4. The register address is 0x3129 which is written with a value of 0x80

Write command: board.WriteI2C(0xC4, 0x31, [0x29, 0x80])

Read command: board.ReadI2C(0xC4, 0x31, [0x29, 0x01])

Alternatively, you can also use the following command to read back a single byte: board.ReadI2C(0xC4, 0x31, [0x29])

0 Michael Gilge over 1 year ago in reply to Hamzeh Jaradat

Expert 1720 points

Thanks,

two more question:

1. How would you read 32-bit addresses, e.g. reading I2C target address 0xC4 from address 0x80797877: board.ReadI2C(0xC4, 0x80, [0x79, 0x78, 0x77])?

2. Does the ALP tool support reading a byte in this format:

+1 Hamzeh Jaradat over 1 year ago in reply to Michael Gilge

TI__Guru** 108650 points

Hello Michael,

Almost there. You only need to add the reading length, i.e. 2 bytes.

board.ReadI2C(0xC4, 0x80, [0x79, 0x78, 0x77, 0x02])

Michael Gilge said:
2. Does the ALP tool support reading a byte in this format

not sure why the Target address is listed 2 times!

No, this is not supported to my knowledge.

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DS90UB954-Q1EVM: ALP: Read from 16bit register addresses