Connecting AUBTM-23 Bluetooth module to a 8051 microcontroller

Question

I am doing my final year project and am facing a problem to send data through a mobile device (android) to a AUBTM-23 bluetooth module, which has a RS232 port something similar to this one, which is conected to a 8051 controller serially.

When I try connecting the module to PC and send data from mobile, the data is properly read in hyperterminal with following information:

OK
+CON1:1
data received from mobile device
+DCON:1
OK

+CON1:1-->received when mobile app tries connection with module.

Then the serial data gets transferred, then when the app disconnects I get DCON.

But when I use it with 8051, there is no data transfer.

I searched and found that module is programmed to send these tags(CON, DCON, OK) and also it is designed to be embedded in a host system (which i think 8051 is not) which requires cable replacement function.

1. SO, is it possible to connect the module to 8051 controller?

2. does a serial port really requires a host?

3. Can I make any arrangement for the extra tags (CON, DCON, OK)?

4. And to connect rs232 port serially, i am making use of only 3 pins and leaving the remaining 6 pins unconnected, could that be a problem?

Answer 1

8051 can be used as a host for the AUBTM-23

There are several conditions that could be causing problems and additional information is necessary to correctly diagnose and troubleshoot them. That being said, the following information might be of some assistance.

• You might need a MAX232 (or other TTL to RS232 level converter) between the 8051 UART pins and the RS232 port on the AUBTM-23 device. Otherwise, you may^† be able to bypass the RS232 port and connect the appropriate 8051 UART pins directly to the UART pins on the AUBTM-23 chip.
  ^{† note that this option depends on the voltages used by both chips and additional circuitry (e.g. level shifter) may be required}

• The AUBTM-23 datasheet says that flow control can be either RTS/CTS or None and is configured during factory calibration. When you connected the AUBTM-23 to HyperTerminal, what type of flow control was used?

  • If your AUBTM-23 device uses RTS/CTS (hardware) flow control, you should connect the the RTS and CTS lines to available port pins on the 8051 and add the appropriate code to handle the handshaking.

  • If your AUBTM-23 device does not use flow control, you should be able to use a minimal 3-wire (TX, RX, GND) RS232 connection.

Answer 2

You can use 8051, UART , just write code for sending AT commands check those on hyperterminal whether they woring or not .. then connect TX RX of 8051 to RX Tx of ur module. Be careful to add a voltage divider with 10kand 15k resistors between Rx line of Module,as it should receive only 3.3 v and max232 will output 5v. It will work...