Modem Signalling Over Bluetooth; Break Signal On Rx Line - TDK Module blu2i User Manual

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specified in S Register 519 then the connection is dropped as if an ATH

command was received.

PIO2 (RI), is normally deasserted. When an incoming connection

is detected it will be asserted, until the connection is either answered or

rejected using ATA and ATH respectively. See S Registers 552 & 553

for more details

PIO3 (DCD) will be deasserted when the device is in the

unconnected state. Asserted when a connection is active. See S

Registers 552 and 553 for more details.

PIO5 is either used as GPIO or driven as UART_DTR. When the

unit is configured in pure host mode, this pin is forced into UART_DTR

and is asserted when there is a Bluetooth connection.

GPIO Pins 1,2,3,4 and 5 are available for general purpose use.

6.1 Modem signalling over Bluetooth

The RFCOMM protocol used in Bluetooth for implementing the serial

port profile allows for the exchange of four modem signals. This

information is contained in a special transparent message which

contains bits identified as RTR, RTC, DV and IC which depending on the

type of serial device being emulated maps to DTR or DSR, RTS, DCD

and RI respectively. In addition, this message also includes the ability to

convey a BREAK input from one end to the other.

So to allow for the greatest flexibility and variability in how the modem

control signals are used out in the real world, S Registers 551, 552 and

553 have been provided which allow for any of RTR,RTC,DV and IC to

be mapped to any modem control/status line.

If the host sends a break signal of duration greater than 100ms, then the

blu

module is configured to treat that as a signal to perform a hardware

reset.

This being the case it is not possible to convey a BREAK over Bluetooth

to the peer device.

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