TMS320F28379D: Does the ROM Bootloader support a direction pin when using a RS485 half-duplex transceiver?

HI Ludger, 

You can allocate one of the GPIO pins to control the transceiver. 

Regards, 

Krishna 

Hi Krishna,

thanks for your answer. We do allocate a GPIO pin to control the transceiver during normal firmware operation.

But how/where to allocate the pin so that the ROM Bootloader uses it during SCI-Boot when it has to echo every single byte?

Regards,

Ludger

Hi Ludger,

Please take a look at the TRM here:  https://www.ti.com/lit/spruhx5 SCI-Boot operates according to the design described in Section 4.10.4.2 SCI Boot Mode.  We do not support a configuration where a half duplex connection can be supported automatically in SCI boot mode by the bootloader. We will discuss this internally to see if there is an alternate solution that we can propose.  Can you explain your constraints in more detail, so we understand what problem you are trying to solve a little better. 

Cheers!

Krishna

In case is of any help. We are also interested on this half duplex programming. And if it uses GPIO30 as the control/enable pin....perfect!!

Hi Krishna,

this describes our constrain (again):

'We need to run SCI-Boot over a RS485 half-duplex connection and we are asking ourselves if the ROM Bootloader can control the direction pin needed by the transceiver (MAX485ESA+) that we are using.'

Please discuss internally, because we have some pressure on this project.

Thanks.

Hi Ludger, 

The bootROM code has already been developed and released as part of ROM image.  It is part of the device manufacturing process.  The SCI boot mode is documented in its entirety in the TRM as I explained earlier.  There is no method to control the the direction pin from within the bootROM.  

Thanks,

Krishna

Thanks for your support, Krishna. Now we have a clear statement.