Product Info
Bluetooth Serial Module
AT Command Set
Date : 3 Feb 03 Issue No : 1.9 Doc No : XRBLU020-001SW-0 Page 27 of 38
© TDK Systems Europe Ltd 2003
Connected Max data transfer
All current consumption values in the table below assume that the connection status indication functionality
of the Leds has been disabled by setting S Registers 533 and 534 to 0.
All current values are in milliamps.
Baudrate
9600 38400 115200 460800
3.6v
3.20 3.20 3.20 3.20
Current per Led
5.0v
5.30 5.30 5.30 5.30
Baudrate
9600 38400 115200 460800
3.6v
1.60 1.80 1.96 3.00
Idle Mode, S512=1
5.0v
2.00 2.10 2.30 3.40
3.6v
59.00 59.00 59.00 59.00
Wait for Connection Or Discoverable Mode, AT+BTP
S508=S510=640, S509=S511=320
5.0v
65.00 65.00 65.00 65.00
3,6v
2.75 2.94 3.10 4.12 Wait for Connection Or Discoverable Mode, AT+BTP
S508=S510=1000, S509=S511=11
5.0v
3.26 3.36 3.55 4.63
3.6v
50.00 50.00 50.00 50.00
Inquiring Mode, AT+BTI
5.0v
54.00 54.00 54.00 54.00
3.6v
50.00 50.00 50.00 50.00
Connecting Mode (ATDxxx)
5.0v
54.00 54.00 54.00 54.00
3.6v
6.00 6.10 6.40 7.20
Connected Mode (No Data Transfer)
5.0v
7.20 7.20 7.40 8.20
3.6v
21.50 22.50 24.50 32.50
Connected Mode (Max Data Transfer)
5.0v
24.50 26.00 28.00 36.00
As can be seen, the current drain while waiting for a connection or discoverable mode is about 30 times
higher than in idle mode. This is when the page/inquiry scan duty cycle is 100%. These modes gives the
quickest response to a page or inquiry request from a remote peer.
It is possible to reduce the duty cycle down to as low as 0.5% at the expense of response time. The
response time can be specified via S Reg 508 and 510 for page and inquiry respectively, where the worst
case response time can be as high as 2.5 seconds. Then the duty cycle can be varied by changing the
value of S Regs 509 and 511 appropriately.
For example, if SReg 508 and 510 are both set to 1000ms and SReg 509 and 511 are both set to 11ms
then the duty cycle is reduced to 1%, this means that average current drain at 5.0v will be 2% of 65mA
plus the normal idle mode current, that is, it is as low as 2.75mA. However, in this case, it can take up to 1
second to establish a connection.