m01_debug_if.md

OBC Debug Interface

General description

The OBC debug interface is a serial communication link which is available at the umbilical connector of the cubesat. With this interface all operations prior to launch (and integration into the launch box) can be executed via connected ground equipment.

 

UART-specifications

baud rate	databits	parity	stop
9600	8	none	1

Commanding

On Rx Line the OBC reacts to received commands. The format of a command is:

<cc> [par1 [par2 [...]]]<LF>

where

• <cc> is a single command character. e.g. ‘s’ for the “Read Sensors”-command.

• par1...parX are optional parameters separated by a single blank ‘ ‘ (0x20). Count and type of parameter is determined by specific commands. Either a numeric value or a string can be used. (At this moment there is no string marker (”) usable, so a string with blanks can not be used as a single par! -> use ‘_’ or ‘-’ instead.)

• <LF> is the line feed character: 0x0a.

  Note: not all commands are available on all tagret hardware.

command	params	description	obc	dev
‘s’	-	reads all on board sensor values. triggers the “<sens>-0x01” event.	x
‘c’	-	power off the SD-Card	x
‘C’	-	power on the SD-Card	x
‘R’	<blockNr>	reads one block from SD-Card and triggers the “<sys>-data” event.	x
‘r’	<c><adr><len>	reads a number <len> bytes from <adr> of mram chip number <c> (0...5). It triggers a “<sys>-data” event.	x
‘w’	<c><adr><b><len>	writes the data byte <b> for <len> times starting at <adr> of mram chip number <c> (0...5).	x
'p'	<abcd|ABCD>	powers on or off one or more sidepanels. e.g "p ABcD" powers 3 of the 4 sidepanels. Blue LED shows on and goes off if current limiter detects short circuit	x
‘O’	<name>	sets the hardware instance name	x
'N'	<name>	sets the sd-card name	x
'i'	-	gives general information about obc board, versions, ....	x
'T'	-	gives the current UTC time in RTC and TLE (juliandayfraction) format	x	x
't'	<date> <time>	sets the UTC time to d´the given date / time. Format: yyyyMMdd hhmmss	x	x
---	---	---	x
'h'	<pinIdx> <mode>	sets an GPIO pin to mode (0: initVal, 1: high, 2: low, 3: slow blink, 4: fast osz.)	x
'm'	<pinIdxIn> [<pinIdxOut>]	mirrors the GPI input pin to the GPIO output pin	x
'5'		Thruster all register read request.	x
'6'	<register index>	Read request to single thruster register.	x
'7'	<register index> [<value>]	Set request for a single thruster register.	x
'S'	<srscmd> [<value>]	sends a command to the SRS submodule.		x
	p	SRS command 'Power Off' (only commands over I2C if submodule was ON)		x
	P	SRS command 'Power On' (only commands over I2C if submodule was OFF)		x
	t	Syncs the SRS to current OBC timestamp. (set either with 't' or over GPS-UART)		x
	T	retreives the SRS unix timestamp		x
	s [<type>]	retreives the SRS Status (type=1: default/common; 2: extended; 3: both		x
	I	retreives all 3 Interval data from SRS		x
	i [<type> [<val>]]	sets the Interval of <type> to the value (type=1:default/fgdos, 2:radfet, 3:sram) (default value: 1000)		x
	x	sends shutdown to SRS		x
	d	initiates data transfer from SRS (gets Addresses to fetch and receives all available data)		x
	d <start>[<end>]	initiates data transfer from SRS for the specified address range		x

Valid pinIdx for command 'h' and 'm' can be found in the hardware abstraction include file in source code.....

Events

Events are sent by using a frame start/end Character of 0x7e. If a databyte of 0x7e (or 0x7d) has to be transmitted this byte is escaped by using the escape char: 0x7d and the escaped data byte is XOR-ed with 0x20.

So one frame looks like this:

0x7e <Mod> <SevId> <byte0> <byte1> ... 0x7e

where

• <Mod> is the module number - the originator of the event.

• <SevId> is composed as 2+6 bit: sseeeeee.

  • ss: the 2 high bits hold the severity (00 - Info, 01 - Warning, 10 - Error, 11 - Fatal)

  • eeeeee: the 6 low bits are the event ID. This ID is specific to each module.

 

Modules

module number	module name
0x00	climb application layer
0x01	timer
0x02	sensors
0x03	memory
0x04	gps
0x06	srs
0x80	mram
0x81	sdcard

 

Events

module-nr/event-id	format	description
0x00 / 0x02	n bytes	raw data
0x00 / 0x03	n chars	a simple ASCII string
--------------------	---------	----------------------------
0x02 / 0x01	6 float	sensor values:
	[0]	supply voltage in V
	[1]	current OBC in mA
	[2]	current side panels in mA
	[3]	temperature (LM19) in °C
	[4]	temperature (SHT3X) in °C
	[5]	humidity in %
--------------------	---------	----------------------------
0x01 / 0x03		UTC time was synchronized
	uint32	current reset number
	double	old UTC Offset
	double	new UTC Offset
	byte	Sync Source (1 GPS, 2 Cmd, 3 RTC)
--------------------	---------	-----------------------------
0x06 / 0x02	2 bytes	Power On executed (I2cdata)
0x06 / 0x03	2 bytes	Power Off executed (I2cdata)
0x06 / 0x04	8 bytes	UnixTime
0x06 / 0x05	n bytes	Status info (n depends on type)
0x06 / 0x06	3x uint32	Intervals (answer to 'S I')
--------------------	---------	-----------------------------