I was following a tutorial to program arduino over bluetooth. http://makezine.com/projects/diy-arduino-bluetooth-programming-shield/
This is what I have done:
Installed latest arduino software.
Setup hc-05 module with the following commands: AT+ORGL AT+ROLE=0 AT+POLAR=1,0 AT+UART=115200,0,0 AT+INIT
This resets to factory settings, sets it as salve module and sets baud rate.
Here might be the first issue. I have first tried baud rate of 9600 to match my arduino baud rate. With 9600 baud rate I was able to open arduino serial console and see serial output from my arduino Pro mini printed. I was suggested elsewhere that this baud rate does not need to match arduino baudrate and should remain at 115200 but with this baud rate I get no serial output. How does this work?
Another issue is that the diagram shows pin 32 of hc-05 needs to be connected to arduino rst pin. I have done that but got not in sync error. The diagram shows a 1uf capacitor and 2 resistors. If I understand correctly 2 resistors are to reduce voltage to 3V from 5V. I dont need them since my arduino outputs 3.3V already. Am I right in thinking this?
I did not have 1uf capacitor so I recovered a 140nf SMD cap from scrap pcb. I still got the same issue when trying to program. What is the purpose of this cap and does it need to be 1uf? I also tried 10uf cap with same results. With rst pin connected my arduino resets when serial console is opened or when programming.
Can anyone see any causes of the not in sync error?
I did some more testing and here's what I found:
With hc-05 module baud rate set at 9600 and direct pin 32 to rst connection I get first few lines of output in the serial console then nothing presumably due to it resetting constantly or something similar. With the 140nf capacitor connected between pin 32 and rst pin on arduino the serial console prints all values as normal. So it seems the capacitor is doing something but still can't program. When I try I get this error:
avrdude: stk500_getsync(): not in sync: resp=0x4c
this is a little different from the error I got with 115200 baud rate. "resp=0x4c" was "resp=0x00" then.