Jaws - DSN Powerdown Feature

TODO: some description, use cases etc.

Terminal Command

dsn get|set btpwdown, for a detailed description have a look at JAWS - Terminal Commands

Modifications in BTnut

  1. disable buskeeper for external RAM
  2. set AS0 = 1 to remain Timer0/RTC in SLEEP_MODE_PWR_SAVE mode
  3. disable ADC
  4. unprogram BODEN, OCDEN and JTAGEN fuse
  5. disable Watchdog timer
  6. set PALE to tristate

code changes:

  1. cbi(XMCRB,XMBK)
  2. undef NUT_CPU_FREQ, default in BTnut
  3. cbi(ADCSR,ADEN)
  4. hfuse = 0xc0, lfuse = 0xbf, SPI programmer needed
  5. wdt_disable(), if enabled
  6. cbi(CC1000_CONFIG_PORT_REG,CC1000_PALE), done in CVS HEAD 2007-04-10

Current Consumption Measurements

BTnode runs Jaws and is supplied directly with 3.3 V. The whole current consumption of this platform is presented, starting from a connected state with Bluetooth.

In GUI mode, there is not much saving potential, because the BTnode have to wait after terminal commands and should wake up from the serial line:

In DSN mode, there is more saving potential, because no terminal commands are expected on the serial line:

With SLEEP_MODE_PWR_SAVE, there is a little more saving. But there is a (hopefully linear) deviation from the timer:

The suggested modifications from above chapter are already included in these measurements. Without the changes an additional current consumption of between 0.25 and 0.35 mA was observed...