Michael Lyle edited this page Jul 4, 2016 · 7 revisions

Welcome to the openLager wiki! OpenLager is a "better openlog":

  • It's faster-- 4 bit SD interface clocked at 19.2MHz with DMA.
  • It has buffer memory to ride out times when the SD card is busy-- 125kbytes in current firmware.
  • It fits in a smaller form factor.
  • ESD protection (series resistors) on input pins.
  • And it has a flip-up microSD connector that is better at retaining the card in crashes and hard landings.

OpenLager is easy to use with async serial. First, wire according to the diagram below (an example of an OpenPilot-style connector is in the drawing). Note that you should attach the flight board's TX to openlager's RX pin!

Cabling diagram

OpenLager has an onboard regulator and can be powered with 3.3-5.5V (the regulator dropout voltage is low enough that the SD card will still work properly at 3.3V input).

Next, insert an microSD card and apply power. (Recommended card: SanDisk Extreme Pro 8GB )

Remove power; remove the card, and attach it to your computer. You'll find openLager has written a file to it called lager.cfg:

{
	"startupMorse" : "",
	"useSPI" : false,
	"baudRate" : 2000000,
	"preallocBytes" : 104857600,
	"preallocGrow" : false
}

The important field to change is baudRate -- set it to the speed of the serial you'll be using for logging. dRonin supports 115200, 250000, 1500000, 2000000, and 2470000 bits per second. Cleanflight prefers 250000 bits per second, etc.

The green LED is on always when power is applied, and the red LED blinks with activity when the card is writing. After 200ms of inactivity, the buffers on openLager will be forcibly flushed. If power is suddenly removed, the file may not be completed in the filesystem; this can be changed by setting preallocGrow to 'true' at the possible cost of garbage being present at the end of the file in this scenario.

The firmware for openlager may be updated by putting an appropriate firmware image called lager.bin on the card.

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