Bluetooth HC-05 and HC-06 interference .

[MichaelaJoy]

granddad: I believe you do. IIRC, it serves the same purpose as a grid leak resistor.

 

[Nigel Goodwin]

granddad: I believe you do. IIRC, it serves the same purpose as a grid leak resistor.

As the gate is connected directly to the output of a logic gate, it will be switched either high or low, so the 'gate leak' isn't required, but won't do any harm and is good practice.

 

[granddad]

Thanks for replies.. Good practice is fine by me.. ordered some 1/8 resistors to go on the ssop board..

 

[Pommie]

R2 is not needed, what you need is to tie up/down the pin that is going to turn this on - assuming you want it to power up with it off.

Mike.
Edited, mixed up top side drivers with Pfets.

 

[granddad]

The power for BT got a bit complex. the SW (4) needed to be able to switch OFF the HC socket if the control enabled the switch , but not turn the socket ON .. if control was OFF ... result !

One Enable for the 4 SW'es is low to enable the OFF for the 4 sockets, also Voltage level changes were needed .

 

[Pommie]

That looks rather complex, why can't you just switch the GND line with a logic level mosfet or an NPN transistor?

Mike.

 

[granddad]

Mike .. I am a bit wary of supplying Volts to IC pins with no or floating GND. these modules have a LDO regulator not sure how they behave with no gnd, also TX RX can have voltage on them directly into the wireless IC...

 

[granddad]

Could have been better laid out ,but splitting the HC-05s from the processor was major re-jig.. result lots of wires and connectors.. time now for 'C'. I still
have 97% program memory of the 512kb to play with ..

 

[granddad]

It seem I'm not as smart as I thought I was... the BT slave was going to be controlled by a PIC12 ... but 8 pins ..make debug difficult , moved up to PIC1814K50 20pin .. lots of mem EE and features... got as far as making the SOIC BOB and PIC board and some code only to find you cannot De-bug this chip with PK3 ..(fail) ( need a debug header ) so now new PIC in place is 18F14K22 . Then problems preserving the Data EEprom , this chip uses the top end of flash memory as Data EEprom , I understand the programmer has to first read the EEdata portion, erase the flash then writes the EE data back, and flashes the program , but telling the PK3 the addresses to save is problematical .. settled for the properties as below.. BT master and slave now messaging and paired .

 

[MichaelaJoy]

Glad to hear that you got it sorted out.

 

[granddad]

I have found understanding the BT serial a bit time consuming... as its not just 'my' RX / TX data format I have to code for , but the slave 'adds' at least one message "+DISC:LINK LOSS" ( at the 're-pair' ) as I stop the link to reprogram the master.. Other than that serial transfer is working.

 

[Nigel Goodwin]

Funnily enough I'm at this very moment playing with an HC-06 (for a project at work), I've just tried connecting and disconnecting my phone from it, and there's no spurious messages here at all.

I've just got the HC-06 wired to an FTDI serial/USB module, and using Termite on my PC as the comms program. In the actual application it will connect to a PIC16F18426, as an external plug-in unit, instead of a plug-in FTDI USB lead (to give the option of using either a laptop via USB, or a phone via BT.

 

[granddad]

Hi Nigel .. well for some time I wondered where this message was coming from .. as it turned up in the PIC18's RX buffer so it could have come from the 06 or the 05 .. took some time but it from the HC-06 I had two PC terminals running on FTDI , monitoring TX and RX on the 06 to catch it.. from master / slave power on all is well 05 pairs with the 06 and they pass bytes.. but if i stop the 05.. the 06 after a few seconds ,, produces this message..

My 'commands frame ' for the slave PIC18 start 0xFF ,0x8x ,task, 0x06, 0xEE. , for no particular reason .. the 'D' task is send your BT address name and pass code. ( this has been read by the PIC on power up and stored in EEprom...) Could be a parameter in the 06 , or FW version ..