Power Management

Introduction

The BGX supports two power modes: Active Mode and Sleep Mode.

Active Mode

In active mode, the BGX has the following configuration:

• BLE Connection Enabled
• BLE Advertising Enabled
• BLE Scanning Enabled
• UART Enabled

Sleep Mode

Sleep mode is a low power state that cannot maintain an active BLE connection. In sleep mode, the BGX has the following configuration:

• BLE Connection Disabled
• BLE Advertising Enabled
• BLE Scanning Enabled
• UART
  • Disabled if UART Baud Rate ( ua b ) > 9600
  • Enabled if UART Baud Rate ( ua b ) <= 9600

The System Sleep Mode variable ( sy s m ) determines whether all active advertising and scanning operations will be shut off when transitioning from active mode to sleep mode:

• sy s m = radio : The BGX will not terminate any active advertising and scanning operations when entering sleep mode.
• sy s m = deep : The BGX will terminate all active advertising and scanning operations before entering sleep mode.

A BGX that is in sleep mode will automatically enter active mode if a BLE connection is established between it and another device.

In sleep mode, the UART is still operational if its baud rate ( ua b ) is 9600 bps or less. If it is greater than 9600 bps, the UART is not operational, and the host controller must wake the BGX before using the UART.

If UART flow control ( ua f ) is enabled and the UART is not operational due to the device being in sleep mode, the UART will deassert its RTS pin to indicate to the host that it cannot not receive UART data.

Power Modes Diagram

The Diagram below illustrates the power modes and entry methods into each mode.

Additional Notes

The Wake on CTS variable ( sy w c ) only applies when the UART baud rate ( ua b ) is greater than 9600. For baud rates of 9600 and below, the host can send the wake command ( wake ) via the UART to wake the device.

The Wake on CTS variable ( sy w c ) setting only takes effect when the device transitions from Active Mode to sleep mode. For example, if the UART baud rate ( ua b ) is 9600 and Wake on CTS ( sy w c ) is 1, the Wake on CTS feature will be disabled when the device enters sleep mode. While in sleep mode, the UART is operational, so the user could set the baud rate ( ua b ) to 115200. At this point, the user might expect a falling edge on CTS to wake the device from sleep. However, the device will not wake, because there was no power state transition to force the new Wake on CTS setting to take effect.

Current Consumption

The following tables show the typical average current consumption for both the BGX13P and BGX13S while performing different operations.

Version Notes: All power measurements were performed on BGX13 Firmware Version 1.2.2045.0 .

Note : There can be considerable (on the order of +/- 25%) variation around these typical average values in various operating environments, particularly when scanning and advertising at short intervals.

Note : The UART was not actively transmitting or receiving data when these measurements were taken. If the UART is active, the BGX will consume more current than is shown.

Note : The Establishing Connection operation occurs during the time between issuing the connect command ( con ) and establishing the BLE connection or the command timing out. When a connection is successfully established, this period of time is typically in the range of 100 to 500 milliseconds. However, when a connect command fails with the Timeout response (see Response Error Codes , the BGX will consume this amount of current for the entire duration of the timeout.

Table: BGX13P Current Consumption

Table: BGX13S (with Low-Frequency Crystal) Current Consumption

Table: BGX13S22GA-V31/R (without Low-Frequency Crystal) Current Consumption