RFM12 ERRATA

RFM12 Wireless module discussion.

RFM12 ERRATA

Postby seaton » Wed Aug 13, 2008 2:27 am

Any ERRATA/Problems to do with the RFM12 modules can be added to this topic along with any workarounds.
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia

Re: RFM12 ERRATA

Postby seaton » Wed Aug 13, 2008 2:29 am

From the manufacturers:

The clock output (Pin8) may generate high clock spurs in the RF output spectrum.

It is not recommended to use the clock output (Pin8). It can be disabled by setting the “dc” bit in the Power Management Command to (1). The next product revision is intended to solve the problem.
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia

Re: RFM12 ERRATA

Postby seaton » Wed Aug 13, 2008 2:31 am

From the Manufacturers:

The internal reset circuitry is sensitive to noise or periodic disturbing signals present on VDD line. The part might stay in reset state if the supply line is not smooth enough.

Apply extensive filtering on the VDD line, especially in the 100Hz –10kHz range to keep the level of the disturbing signal below 10mVp-p or if it is possible, shift the frequency of the disturbing signal (for example in case of an SMPS change the switching frequency). The next product revision is intended to solve the problem.
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia

Re: RFM12 ERRATA

Postby seaton » Wed Aug 13, 2008 2:32 am

From the Manufacturer:

The reference block for low battery detector and wake-up timer needs up to 2 seconds for start-up after initial power ramp-up. (Not specified in datasheet)
After initial power ramp up, a wait time of 2 seconds will be needed for the reference block to start.
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia

Re: RFM12 ERRATA

Postby mihaigalos » Sun Aug 24, 2008 8:36 pm

There is an errata on RFM01 ,RFM02 and RFM12 modules concerning the status register. I am convinced that the signal strength is Present within those bits. As the manufacturer has not updated the datasheets yet, anybody have any clue to the bit mappings in this 16-bit register ?
mihaigalos
 
Posts: 4
Joined: Sun Aug 24, 2008 8:32 pm
Location: Timisoara, Romania

Re: RFM12 ERRATA

Postby seaton » Mon Aug 25, 2008 2:10 am

mihaigalos wrote:There is an errata on RFM01 ,RFM02 and RFM12 modules concerning the status register. I am convinced that the signal strength is Present within those bits. As the manufacturer has not updated the datasheets yet, anybody have any clue to the bit mappings in this 16-bit register ?


I would very much like to be able to get this somehow. The only way I've found out so far is ARSSI and only on the SMD modules, but this requires a wire to be soldered to an analogue pin onboard the smd (it is not bought out to an external pin) so if you want to use DIP module, no ARSSI !
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia

Re: RFM12 ERRATA

Postby mihaigalos » Tue Aug 26, 2008 6:28 pm

seaton wrote:I would very much like to be able to get this somehow. The only way I've found out so far is ARSSI and only on the SMD modules, but this requires a wire to be soldered to an analogue pin onboard the smd (it is not bought out to an external pin) so if you want to use DIP module, no ARSSI !



whaaat ?! No way :) Indeed, none of the RFM01 , RFM02 or RFM12 feature any pin for the ARSSI , but they do feature DRSSI. Now, this is a bit tricky beause DRSSI is not a bit field, but a bit. It's true for Signal Strength above a treshold and false otherwise. One aproach is to program the treshold and then decrementaly decrease its value with a predefined resolution to yield the signal strength.
mihaigalos
 
Posts: 4
Joined: Sun Aug 24, 2008 8:32 pm
Location: Timisoara, Romania

Re: RFM12 ERRATA

Postby seaton » Wed Aug 27, 2008 12:59 am

mihaigalos wrote:
seaton wrote:I would very much like to be able to get this somehow. The only way I've found out so far is ARSSI and only on the SMD modules, but this requires a wire to be soldered to an analogue pin onboard the smd (it is not bought out to an external pin) so if you want to use DIP module, no ARSSI !



whaaat ?! No way :) Indeed, none of the RFM01 , RFM02 or RFM12 feature any pin for the ARSSI , but they do feature DRSSI. Now, this is a bit tricky beause DRSSI is not a bit field, but a bit. It's true for Signal Strength above a treshold and false otherwise. One aproach is to program the treshold and then decrementaly decrease its value with a predefined resolution to yield the signal strength.


Thats an interesting way of doing it. I was aware of a DRSSI that is basically a bit indicator, but I would like something a bit more to get a value for the RSSI, i.e. 0-255 indicating signal strength. I spoke to Hope as their spec sheets said they do both DRSSI and ARSSI, their response I've noted on my blog http://blog.everythingrobotics.com/2008 ... /#more-135
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia

Re: RFM12 ERRATA

Postby seaton » Wed Aug 27, 2008 9:24 am

mihaigalos wrote:There is an errata on RFM01 ,RFM02 and RFM12 modules concerning the status register. I am convinced that the signal strength is Present within those bits. As the manufacturer has not updated the datasheets yet, anybody have any clue to the bit mappings in this 16-bit register ?


Response from an email I sent to the manufacturers:
unfortunately the DRSSI value available only as a bit and can not read out the RSSI value via the SPI port. The DRSSI bit is implemented as a voltage comparator inside the chip so the ARSSI is not digitalized inside.
Regards


So it looks like either using ARSSI value with External A/D (only available on SMD via soldering a wire on) or using the DRSSI bit are the only options :(

arssi.png
ARSSI on SMD
arssi.png (25.5 KiB) Viewed 13019 times


Stephen...
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia

Re: RFM12 ERRATA

Postby mihaigalos » Sun Jan 18, 2009 11:20 am

Seaton, did you actually solder a contact on the SMD version of RFM12, on the module itself, for ARSSI?

How did that work out:) ?
mihaigalos
 
Posts: 4
Joined: Sun Aug 24, 2008 8:32 pm
Location: Timisoara, Romania

Re: RFM12 ERRATA

Postby seaton » Sun Jan 18, 2009 1:43 pm

mihaigalos wrote:Seaton, did you actually solder a contact on the SMD version of RFM12, on the module itself, for ARSSI?

How did that work out:) ?


yes check out the post http://blog.everythingrobotics.com/2008/06/17/rfm12-tutorial-part2/
seaton
Site Admin
 
Posts: 134
Joined: Mon Jan 23, 2006 8:48 am
Location: Bunbury, Western Australia


Return to RFM12

Who is online

Users browsing this forum: No registered users and 1 guest

cron