LP4DSM won't bind! help Plz!
Posted: Tue Oct 14, 2014 7:34 pm
Hello everyone.
I was trying to install the LP4DSM module removed from a parkzone champ boxed transmitter.
I'm having trouble getting it working. The lp4dsm module was working fine in the original transmitter. My turnigy 9x has er9x Ver r813 (latest i believe)
I followed all the treads I could find relating to the install. I have used the 3v3 regulator pad on the 9x main board. I believe this is ok without the dedicated regulator for this low power module. I have sampled voltage at the lp4dsm module to be exactly 3v3 powered up.
So, that in mind I have power and ground is established and checked for continuity at various ground points.
For signal I have a 5K (didnt have 4k7) pull up between 3v3 and SIG on the lp4dsm. Also on SIG we have the diode. I am using 1N4005 (didnt have 1N4001) should be fine right? I also tried 1N4148 (sub for 914 diode) neither diodes let me bind.
Let me assume and correct me if I'm wrong. But the pullup 4K7 resistor should have our SIG line floating high at 3v3 correct? with the diode from SIG >| to PPM pin on the 9x backboard. This being said its expected a low signal on the PPM pin on the backboard would draw the 3v3 float down to a lower voltage.
At least that is what I expect to see happen based on the schematics and instructions I have seen.
Of course In the model menu I set it for proto = DSM2 and set fot LP4/LP5 (also tried dsm2 only and dsm2/dsmx) I also updated the chennel order to the specified TAER.
TROUBLESHOOTING.
Checked 3v3 supply at lp4dsm module 3ve pad.
Checked GND connections.
Check value of pullup = 5K exactly.
Check PPM signal on backboard with O-scope and PPM is present. looks like 12channels?
Check PPM signal at SIG pad of lp4dsm on other side of diode = NO PPM Signal!!!!!
Check SIG pad voltage =0.55v
OK, so I remove diode and PPM conection from lp4dsm and check for 3v3 at SIG. I get only 0.55v after the pullup resistor. This tells me something internal to lp4dsm has it pulled low constantly.
IF lp4dsm has a steady low wouldnt the diode as SIG |< PPM allow PPM to pass through as HIGH pulse from the PPM backboard? I know this is reverse to the intended operation.
Let me note that when I power up with the TRN switch held to enter a BIND mode I get no LED activity on the lp4dsm IF I invert the diode I get 3 flashes from the lp4dsm with the TRN switch held at start up for BIND mode. Yet I dont get my little chanp to bind.
I now a little electronics and it sure seems like everyone else has 3v3 at SIG after pullup?
thanks for your time and help!!!
I was trying to install the LP4DSM module removed from a parkzone champ boxed transmitter.
I'm having trouble getting it working. The lp4dsm module was working fine in the original transmitter. My turnigy 9x has er9x Ver r813 (latest i believe)
I followed all the treads I could find relating to the install. I have used the 3v3 regulator pad on the 9x main board. I believe this is ok without the dedicated regulator for this low power module. I have sampled voltage at the lp4dsm module to be exactly 3v3 powered up.
So, that in mind I have power and ground is established and checked for continuity at various ground points.
For signal I have a 5K (didnt have 4k7) pull up between 3v3 and SIG on the lp4dsm. Also on SIG we have the diode. I am using 1N4005 (didnt have 1N4001) should be fine right? I also tried 1N4148 (sub for 914 diode) neither diodes let me bind.
Let me assume and correct me if I'm wrong. But the pullup 4K7 resistor should have our SIG line floating high at 3v3 correct? with the diode from SIG >| to PPM pin on the 9x backboard. This being said its expected a low signal on the PPM pin on the backboard would draw the 3v3 float down to a lower voltage.
At least that is what I expect to see happen based on the schematics and instructions I have seen.
Of course In the model menu I set it for proto = DSM2 and set fot LP4/LP5 (also tried dsm2 only and dsm2/dsmx) I also updated the chennel order to the specified TAER.
TROUBLESHOOTING.
Checked 3v3 supply at lp4dsm module 3ve pad.
Checked GND connections.
Check value of pullup = 5K exactly.
Check PPM signal on backboard with O-scope and PPM is present. looks like 12channels?
Check PPM signal at SIG pad of lp4dsm on other side of diode = NO PPM Signal!!!!!
Check SIG pad voltage =0.55v
OK, so I remove diode and PPM conection from lp4dsm and check for 3v3 at SIG. I get only 0.55v after the pullup resistor. This tells me something internal to lp4dsm has it pulled low constantly.
IF lp4dsm has a steady low wouldnt the diode as SIG |< PPM allow PPM to pass through as HIGH pulse from the PPM backboard? I know this is reverse to the intended operation.
Let me note that when I power up with the TRN switch held to enter a BIND mode I get no LED activity on the lp4dsm IF I invert the diode I get 3 flashes from the lp4dsm with the TRN switch held at start up for BIND mode. Yet I dont get my little chanp to bind.
I now a little electronics and it sure seems like everyone else has 3v3 at SIG after pullup?
thanks for your time and help!!!