Re: [Paparazzi-devel] Soft uart possible?

[antoine drouin]

I forgot: paparazzi already has code to decode the spektrum 2.4GHz
satellite receiver
( 
http://svn.savannah.gnu.org/viewvc/paparazzi3/trunk/sw/airborne/booz/radio_control/booz_radio_control_spektrum.h?revision=3732&root=paparazzi&view=markup
)


On Mon, Sep 14, 2009 at 12:14 PM, antoine drouin <address@hidden> wrote:
> The SSP port of the LPC2148 is exposed and usualy unused on tinys.
> This port is both high troughput and low overhead. A chip such as the
> SC16IS752  ( http://www.nxp.com/acrobat/datasheets/SC16IS752_SC16IS762_7.pdf)
> could be used to add two hardware uarts. I've drawn the board but
> never manufactured it (
> http://svn.savannah.gnu.org/viewvc/paparazzi4/trunk/hw/misc/serial_extender.brd?revision=3468&root=paparazzi&view=markup
> )
> At the moment I am working on designing a board using a STM32 instead
> of a LPC2148. The STM32 has 3 uarts
>
> Regards
>
> Poine
>
>
> On Mon, Sep 14, 2009 at 11:26 AM,  <address@hidden> wrote:
>> Hi Timo,
>>
>> Yes, both hardware UART ports are used on the LPC2148 (for GPS and
>> telemetry).
>> The only option for a third UART is via software.
>>
>> I understand that the LPC2148 is 40-60% utilised when running the
>> paparazzi code so there is some remaining capacity available. For low
>> serial speeds, polling a pin would be sufficient. However for high
>> speeds, timers & interrupts would be necessary.
>>
>> The timer and interrupts associated with the PPM input (pin#30/CAP0.2)
>> could be used for software serial input instead. I haven't tried it and
>> not sure if anyone else has.
>>
>> The open-source mikrokopter project has some c code to decode the 115200
>> bit/s serial signal from a 2.4 GHz Spektrum satellite receiver at:
>> http://svn.mikrokopter.de/mikrowebsvn/filedetails.php?repname=FlightCtrl
>> &path=%2Ftags%2FV0.74d%2FSpectrum.c Although based on the ATMega644P
>> using a hardware UART, it could be adapted and implemented in the
>> Paparazzi system. I haven't tried it and not sure if anyone else has. It
>> seems feasible.
>>
>> The alternative is to use the PPM encoder board
>> (http://paparazzi.enac.fr/wiki/Other_Hardware#PPM_Encoder_Board). The
>> Spektrum serial signal could be input on the "servo 1" pin (pin#30/RXD)
>> which can be configured as hardware serial input. The code could then
>> decode the signal and output PPM to the autopilot.
>>
>> Hope this helps.
>>
>> Cheers, Mark
>>
>> -----Original Message-----
>> From: address@hidden
>> [mailto:address@hidden On
>> Behalf Of Timo Drick
>> Sent: mercredi, 2. septembre 2009 01:31
>> To: address@hidden
>> Subject: [Paparazzi-devel] Soft uart possible?
>>
>> Hi all,
>>
>> it would be nice to have some more uart ports at the Twog or Tiny v2.
>> Did anyone try to implement a soft uart.
>> One application would be to read 2.4 Ghz Spektrum receiver data. The
>> satalite receiver send serial data with 115 kBaud data rate. Only a RX
>> uart pin is needed to read the receiver data. If this works no ppm
>> encoder board and only 3 wires are needed.
>>
>> regards Timo
>>
>>
>> _______________________________________________
>> Paparazzi-devel mailing list
>> address@hidden
>> http://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>>
>>
>>
>>
>> _______________________________________________
>> Paparazzi-devel mailing list
>> address@hidden
>> http://lists.nongnu.org/mailman/listinfo/paparazzi-devel
>>
>