Post by papa on Sept 22, 2016 19:58:06 GMT
The Gateway described in this thread (especially the Oct 8, 2015 at 6:40pm post) is a Buono Uno Arduino compatible (switched to 3.3 volt operation) plus an W5100 Ethernet Shield (ES) inserted on top plus an RFM69 radio connected to the needed Ethernet Shield sockets. These have worked well for me, including a gateway that's run for over a year.
However, recently jimkernsjr reported problems with this gateway: lockups happening, wrong voltage found at the ES's 3.3 volt socket, & suspicion that the lockups are due to the RFM69 radio getting voltages out of its safe range. Investigating, I confirmed Jim's concerns & additional concerns. You can read the whole investigation at the thread, "Gateway Lockups and strange voltage problem on 3v3 line." I'll try to give the key info here.
If you have built such a gateway, you need to make a correction to prevent damaging the gateway's RFM69 radio & causing an unreliable gateway.
My key confirmations & findings:
1) With NO Ethernet Shield, a Buono Uno switched to 3.3 volt operation has a 3.3 volt socket that is truly that & no digital sockets show more than 3.3 volts.
Thus an RFM69 radio should be safe when (for a NODE) it is installed on a Buono Uno ALONE that is switched to 3.3 volt operation.
2) When an Ethernet shield is installed on a Buono Uno, the voltages seen at various Ethernet shield sockets are always as if the Buono is switched to 5 volt operation:
That is, even switched to 3.3 volt operation, the Ethernet Shield's 3.3 volt socket & key RFM69 sockets like D8, D10, & D11 are nearer to 5 volts. Note: According to the data sheet, a RFM69 radio's safe range is 1.8 - 3.6 volts.
The following fix (for the problem in item 2) applies only to a Gateway built from a Buono Uno Arduino compatible (switched to 3.3 volt operation) plus Ethernet Shield plus RFM69 radio:
Rising up from the Buono are a group of 6 pins called ICSP, one pin is VCC (power)
Holding the Buono as it's oriented in the picture below, VCC is the upper right pin (& is labeled in the pic)
<< Click on the pic for a larger view.
The ICSP pin labeled "1" is MISO, & VCC is pin 2, the pin paired with pin 1.
The hack fix is ...
bend out only the Buono's ICSP VCC pin so it will not connect to the matching Ethernet Shield (ES) socket above.
Sufficiently insert all the other ES pins into the Buono Uno which is switched to 3.3 volt operation.
Have a gateway sketch uploaded / installed to the Buono. When the Gateway is powered, the ES sockets' voltages should be:
3.3 volt socket = about 3.3 volts. D8, D10, & D11 sockets never going higher than 3.3 volts.
All the above should be safe for the RFM69 radio.
Yet to be seen: 1) Does the bent pin hack cause other problems that compromise using this fix?
2) Will RFM69 radios develop premature problems & failures if they had been previously used on a Gateway without this hack.
P.S. I incorporated the hack fix into the main Gateway assembly instructions at the Oct 8, 2015 at 6:40pm post in this thread.
However, recently jimkernsjr reported problems with this gateway: lockups happening, wrong voltage found at the ES's 3.3 volt socket, & suspicion that the lockups are due to the RFM69 radio getting voltages out of its safe range. Investigating, I confirmed Jim's concerns & additional concerns. You can read the whole investigation at the thread, "Gateway Lockups and strange voltage problem on 3v3 line." I'll try to give the key info here.
If you have built such a gateway, you need to make a correction to prevent damaging the gateway's RFM69 radio & causing an unreliable gateway.
My key confirmations & findings:
1) With NO Ethernet Shield, a Buono Uno switched to 3.3 volt operation has a 3.3 volt socket that is truly that & no digital sockets show more than 3.3 volts.
Thus an RFM69 radio should be safe when (for a NODE) it is installed on a Buono Uno ALONE that is switched to 3.3 volt operation.
2) When an Ethernet shield is installed on a Buono Uno, the voltages seen at various Ethernet shield sockets are always as if the Buono is switched to 5 volt operation:
That is, even switched to 3.3 volt operation, the Ethernet Shield's 3.3 volt socket & key RFM69 sockets like D8, D10, & D11 are nearer to 5 volts. Note: According to the data sheet, a RFM69 radio's safe range is 1.8 - 3.6 volts.
The following fix (for the problem in item 2) applies only to a Gateway built from a Buono Uno Arduino compatible (switched to 3.3 volt operation) plus Ethernet Shield plus RFM69 radio:
Rising up from the Buono are a group of 6 pins called ICSP, one pin is VCC (power)
Holding the Buono as it's oriented in the picture below, VCC is the upper right pin (& is labeled in the pic)
<< Click on the pic for a larger view.The ICSP pin labeled "1" is MISO, & VCC is pin 2, the pin paired with pin 1.
The hack fix is ...
bend out only the Buono's ICSP VCC pin so it will not connect to the matching Ethernet Shield (ES) socket above.
Sufficiently insert all the other ES pins into the Buono Uno which is switched to 3.3 volt operation.
Have a gateway sketch uploaded / installed to the Buono. When the Gateway is powered, the ES sockets' voltages should be:
3.3 volt socket = about 3.3 volts. D8, D10, & D11 sockets never going higher than 3.3 volts.
All the above should be safe for the RFM69 radio.
Yet to be seen: 1) Does the bent pin hack cause other problems that compromise using this fix?
2) Will RFM69 radios develop premature problems & failures if they had been previously used on a Gateway without this hack.
P.S. I incorporated the hack fix into the main Gateway assembly instructions at the Oct 8, 2015 at 6:40pm post in this thread.
