TMS320F28035: GPIO input hysteresis for F2803x devices

Sheldon He

Part Number: TMS320F28035

Hi expert,

I don't see voltage input hysteresis marking in F2803x's datasheet like what is written in F28004x's datasheet.

1. May I know if F2803x has the same input hysteresis parameters?

2. Does this hysteresis paramter apply to all the GPIO and digitial peripheral's (input) on this device? (We see marking of this paramter in I2C part)

Thanks

Sheldon

over 3 years ago

0 MatthewPate over 3 years ago

TI__Guru 71835 points

Sheldon,

I'll need another day to look into this more. Since this parameter is not in the DS I can't say it will be the same as the F28004x. If I use the I2C number @3.3V VDDIO it gives a slightly higher number of 165mV vs the F28004x 150mV.

I'll reply again tomorrow with an update.

Best,

Matthew

0 Sheldon He over 3 years ago in reply to MatthewPate

TI__Expert 8585 points

Hi Matt,

Do you have any update here?

Thanks

Sheldon

0 MatthewPate over 3 years ago in reply to Sheldon He

TI__Guru 71835 points

Sheldon,

Sorry for the delay, I am still waiting on a reply from our design team with regard to this request. I will provide an update by Monday EOB US time.

Best,

Matthew

0 MatthewPate over 3 years ago in reply to MatthewPate

TI__Guru 71835 points

Sheldon,

I'm still working with design on this. Just to give some early info I think that the F28035 is going to be very similar to F28004x within 20mV or so. I just need to get some final data before I feel we can close this.

Will update again tomm.

Best,

Matthew

0 Sheldon He over 3 years ago in reply to MatthewPate

TI__Expert 8585 points

Hi Matt,

Kindly check if any update here?

Thanks

Sheldon

0 Sheldon He over 3 years ago in reply to MatthewPate

TI__Expert 8585 points

Hi Matt,

Any conclusion here?

Thanks

Sheldon

0 MatthewPate over 3 years ago in reply to Sheldon He

TI__Guru 71835 points

Sheldon,

Following up from our offline conversation. There are a limited set of IOs and support pins that have ~400mV of hysteresis on the F2803x. These are the GPIOs that are dual function JTAG pins, as well as the XRSn and X1 pins.

The standard GPIOs on the F2803x do not have hysteresis like the F28004x device. With that said, the default input signal conditioning for these inputs is a synchronous path, meaning that once the state is latched the noise would need to be such that it extended to another clock cycle to propagate. If the user desires additional protections, they can choose to use the qualification logic on the input chain as well.

Best,

Matthew

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TMS320F28035: GPIO input hysteresis for F2803x devices