Lpc2000

Hello,

Does anyone know if it is possible to modify the philips bootloader
code for the LPC chips to allow the bootloader to work in a half
duplex RS485 mode?

I am building a board who's primary form of communication will be a
2Wire half duplex RS485 link. To upload new firware at the PC end I
can easily use an RS232 to RS485 converter that has automatic gating.
I.e. it will switch between transmit and receive modes automatically.
the problem is the ARM end.

What I want to do on the ARM is to have one of its port lines control
the transmit receive state of the RS485 chip. This would require a
fairly simple mod to the bootloader code, if I had the source.
Does anyone have any suggestions? or alternative bootloader ideas.

On another tack, does anyone have any ideas about bootloader code for
the LPC214x that can use the USB port. This would be a nice option to
use in our product, use a usb port for firmware upgrading. This sort
of functionality is built into the Atmel SAM7 ARM chips

Thanks

Martin Honeywill

Hi Martin

We have a PC program which checks the boot loader version in an 
LPC210x and loads the newest version if it is found not be be the 
newest know one (there are some problems with older versions but 
many chips still have them) and then loads a user software.

I assume it would not be a big job to modify this to ensure that it 
will also work on half duplex links - RTS line could also be used 
for control.

It takes about 2..3 days of work to knock up such a program.

I did the work for a customer (for factory programming - it is also 
more reliable than the Philips utility, which programs the vector 
check sum at the beginning and so risks a non-starting code if 
interrupted, because it programs the vector check sum block as the 
very last task) and so can not just give it away. If you are 
interested and there is a small demand for such a utility then I 
could probably get a licence agreement which will allow me to 'sell' 
[sorry for the dirty word] the utility for an appropriate fee.

Tell me what you think.

Cheers

Mark Butcher
www.mjbc.ch





--- In lpc2000@yahoogroups.com, "mhoneywill" <martin.honeywill@k...> 
wrote:
> Hello,
> 
> Does anyone know if it is possible to modify the philips bootloader
> code for the LPC chips to allow the bootloader to work in a half
> duplex RS485 mode?
> 
> I am building a board who's primary form of communication will be a
> 2Wire half duplex RS485 link. To upload new firware at the PC end I
> can easily use an RS232 to RS485 converter that has automatic 
gating.
> I.e. it will switch between transmit and receive modes 
automatically.
> the problem is the ARM end.
> 
> What I want to do on the ARM is to have one of its port lines 
control
> the transmit receive state of the RS485 chip. This would require a
> fairly simple mod to the bootloader code, if I had the source.
> Does anyone have any suggestions? or alternative bootloader ideas.
> 
> On another tack, does anyone have any ideas about bootloader code 
for
> the LPC214x that can use the USB port. This would be a nice option 
to
> use in our product, use a usb port for firmware upgrading. This 
sort

> of functionality is built into the Atmel SAM7 ARM chips
> 
> Thanks
> 
> Martin Honeywill

Thanks Mark,

> Hi Martin
> 
> We have a PC program which checks the boot loader version in an 
> LPC210x and loads the newest version if it is found not be be the 
> newest know one (there are some problems with older versions but 
> many chips still have them) and then loads a user software.
> 
> I assume it would not be a big job to modify this to ensure that it 
> will also work on half duplex links - RTS line could also be used 
> for control.
> 
> 
> Tell me what you think.
> 
> Cheers
> 
> Mark Butcher

But its not the PC end that I need to modify its the ARM end. My ARM
device will have one half duplex RS485 port that I want to use to with
the built in ARM ISP firmware. This would mean that the built in ARM
ISP firmware would need to be able to control the Transmit state of
its own RS485 chip.

Thanks for the reply

Martin