specified in S Register 519 then the connection is dropped as if an ATH command was received.
2PIO2 (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
3PIO3 (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.
4PIO5 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.
6.2 BREAK signal on RX line
If the host sends a break signal of duration greater than 100ms, then the blu2i 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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