Using AEROCOMM AC4790-200M RF Module with Propeller

DavidM

Hi,

I am planning to use the AEROCOMM AC4790-200M radio Module with the propeller.
I will be using these in POINT TO POINT ( 2 way serial) and POINT to MULTIPOINT ( one way - broadcast) modes.

I have attached a basic schematic that shows how ( I THINK?) it should be connected. As well as the Pinouts from the Spec Sheet.
I have used the same RX & TX lines that the propeller uses for programming. (P30 & 31)

Q1) When I want to load up the prop with spin code, will the modem misbehave?? I have it set to COMMAND MODE on power up!
Q2) If I want to disable the MODEM ( because of Q1) and use the RX/TX lines should I use a TRANSISTOR/MOSFET to switch on the power to the MODEM?
Q3) Has anyone else used these modems before?, I was planning to use the XBEE PRO, but I need more "ROBUST" protocol ( i.e frequency ) as I will be using these in various "Hostile" environments.
Q4) is it best to run the modem off its own 3.3V regulator?
Q5) I need to be able to monitor the RSSI ( signal strength) remotely as well as locally, this info is available from the API commands ( I think?) instead of use the analog RSSI output ( PIN 13) as this would require some kind of ADC and more lines to the prop.

regards


Dave M

DavidM

I forgot to mention..

Q6) Do I need to create a special ground area/plane for where the modem module sits?


Thanks


Dave M

RW58

I'm using a pair of 4490-200's and was able to get it all working using just the rx and tx lines. -Although your schematic looks much more complete than my method, there are software command strings you can use to exit command mode and load appropriate config settings.

I used P0 and P1 so cannot answer your question about what will happen on startup.··5.0v to the module, 3.3 occasionally resulted in a Low power msg from the eval board.· Haven't gotten to the RSSI/ADC yet, will probably use the 'In Range' pin instead.· I'm not using the 1x1 modules, so ground plane, etc not needed.


'Aerocomm command strings
'Enter AT cmd mode
······· EnterAT········ byte····· $41,$54,$2B,$2B,$2B,$0D
'Client mode
······· Client········· byte····· $CC,$03,$03
'Broadcast mode (1 is addressed mode)
······· Broadcast······ byte····· $CC,$08,$00
'write dest addr (address provided is EVAL BOARD 1)
······· SetDest········ byte····· $CC,$10,$37,$51,$63
'set channel
······· ChangeChannel·· byte····· $CC,$02,$0·········
'exit AT mode
······· ExitAT········· byte····· $CC,$41,$54,$4F,$0D

DavidM

Hi RW58,

You are right about entering command mode via the RX & TX lines, I may try that! As I need to save some prop pins!

the 4490 is slightly different to the 4790 , as it does not have an IN RANGE Status line, This is one of the most important attributes I need to manage, I am hoping that I can do this via the COMMANDS.

I just re read the manual and it says the following, my model can run at 5 v

---

AC4790-1x1: 3.3V, ±50mV ripple
AC4790-200: 3.3 – 5.5V, ±50mV ripple
AC4790-1000*: Pin 10: 3.3 – 5.5V ±50mV ripple
Pin 11: 3.3 ±3%, ±100mV ripple
* Pins 10 and 11 may be tied together, provided the supply voltage never falls below 3.3 V and is capable of
supplying 1.5 A of current.

---

1.5 amps ???? that could be an issue!

thanks

Dave M

ALIBE

I·use AC4790 along w/ Propeller in my robot:

more details in my blog:
http://aliben.wordpress.com/2006/10/24/interfacing-aerocomm-ac4790-with-propeller-chip/
http://aliben.wordpress.com/2006/10/26/testing-the-ac4790-and-propeller-interface-w-alibe-homebase-command-center/
http://aliben.wordpress.com/2006/10/24/aerocomm-ac4790-a-short-introduction/

Nagi


▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"any small object, accidentally dropped, goes and hides behind a larger object."

·
ALIBE - Artificial LIfe BEing. In search of building autonoumous land robot

DavidM

HI ALIBE,

I have seen your links, I read them and used that info to help decide on using the aerocomms instead of the XBEEPRO's

HAve you tried using more that just a pair of modems? I will be planning to use a dozen or so in the one network! with one modem being the master.

I have attached my current PCB design..

What do you think?

Thanks

Dave M

ALIBE

Hi Dave
I have not yet tried to n/w multiple ac4790s. But, that was one of the features of ac4790 that sold me also (for future work). Best of luck w/ your project. I looked at the wiring on the PCB, looks like it should work the way you have set it up.

Thanks

Nagi

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"any small object, accidentally dropped, goes and hides behind a larger object."

·
ALIBE - Artificial LIfe BEing. In search of building autonoumous land robot

DavidM

HI,

I have revised my circuit and have decided to use the AC4490-200M Module instead. As it has IN RANGE status pin,

Q1) Have I hooked up my LED'S correctly?


regards


Dave M