rs485 to rs232 ic for bootloader, rs485 bootloader

[Tim Webster]

Is there ic which can convert from unidirectional rs485 to rs232 for
the purpose of bootloader?

Alternately I am looking for a cortex M4, preferably stm32 source code
for rs485/universal bootloader. It would super if such bootloader
could use key to decrypt and check the signature on the firmware
update.

Thx


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778 317 7769

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[Colin Fitzgerald]

Hi Tim,

485 to 232 is easy to do with a pair of IC's. You need one to convert
485 to TTL and then TTL to 232. No one IC will do this.

It gets a little trickier with bidirectional comms since you need a
microcontroller to detect and manage the direction of the 485 port, but
you indicate you don't need this.

Search DigiKey for 485 and 232 and you'll find a ton of IC's. Let me
know if you need something more specific.

On 3/21/2013 7:48 AM, Tim Webster wrote:
> Is there ic which can convert from unidirectional rs485 to rs232 for
> the purpose of bootloader?
>
> Alternately I am looking for a cortex M4, preferably stm32 source code
> for rs485/universal bootloader. It would super if such bootloader
> could use key to decrypt and check the signature on the firmware
> update.
>
> Thx
>
>


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[Tim Webster]

Sounds like to create a 485 boot loader, I will need to

- add another IC to manage the direction of the 485
OR
- write a bootloader designed to manage the direction of the 485 itself.

Tim

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778 317 7769

[Colin Fitzgerald]

Ya, more or less. Since 485 is a half duplex protocol something must
control the direction of the line...

Modifying the bootloader would be the slickest by far and probably most
reliable since the tx enable needs to be driven before any data is
actually sent..