OpenEC

This page is a placeholder for all information regarding the open source implementation of the XO-1's Embedded Controller (EC).

Email List

http://lists.laptop.org/listinfo/openec

openec@lists.laptop.org

Git Tree

http://dev.laptop.org/git?p=projects/openec;a=summary

OpenEc firmware project

openec is an effort for an open implementation of the firmware on the EC. It currently is in an early stage and not functional yet. Downloading openec to an XO might damage the XO, please do not do so unless you know what you are doing.

Tools for OpenEc

git 

source revision tool

sdcc 

Compiler sdcc 2.7.0 or later (needed) http://sdcc.sf.net (Compiler which generates the binary for the EC)

gcc 

Compiler (optional for openec) the source is currently also compilable with GCC

doxygen 

Source documentation tool (optional), http://www.doxygen.org

LaTeX 

text tool (optional), needed if a pdf version of the documentation should be generated. A html version of the source documentation can be generated without LaTeX

Srecord 

srecord (needed), http://srecord.sf.net, handling of hex (etc.) files (Version 1.36)

Make 

(needed), GNU make, should be there anyway.

D52 

Disassembler (optional), http://www.8052.com/users/disasm/ , generates disassembled file openec.d52

Download software 

spiflash.dic (needed), see http://lists.laptop.org/pipermail/openec/2007-August/000061.html . Forth software to download the EC firmware to the target. Be sure to backup the complete firmware (including manufacturing data) first

Hardware adapter 

serial adapter (needed) http://wiki.laptop.org/go/Image:Serial_adapter.jpg Hardware adapter to download to target. Connects to CN24 and an RS232 null-modem cable (an additional oscillator is needed (66MHz(?) to CN24,Pin5)). Additional instructions are at SPI_FLASH_Recovery. (The instructions there address recovery of the complete flash)

Jumpers 

2 jumpers for Recovery Mode jumper block (see above)

Null modem cable 

(needed) to connect the serial adapter to a serial port

Serial port 

(needed) Not all new PC and very few notebooks still have a serial port (an USB to serial adapter might be additionally needed then)

Terminal Software 

minicom (recommended). Needed to see or capture debugging output. Parameters 115kBaud, 8N1, no handshake - other terminal programs can be used too.

Related Documentation

http://wiki.laptop.org/go/Category.EC

ENE KB3700 Datasheet

http://sdcc.sourceforge.net/doc/sdccman.pdf

Mailing List

• http://lists.laptop.org/listinfo/openec

Getting the source

The source is in the git repository OpenEC and can be browsed online there.

To get this code onto your machine please change to a newly created directory and do:

git-clone git://dev.laptop.org/projects/openec

Compiling on the host for the EC

If the necessary tools are installed it is a simple "make" inside the openec directory:

make

Listing files and a binary file currently named openec.do_not_use.bin are generated. (Intentionally no more details here about how to proceed:)

Compiling on the host for the host

Run make with an additional argument inside the openec directory:

make -f Makefile.gcc

you can then run

./openec.gcc | less

there. The EC specific hardware is not present on the host, so openec.gcc will be of limited use. Running openec.gcc on the host does not endanger the host:)

Files of the C implementation

battery.c    Skeleton for battery handling with the Embedded Controller (key) 
build.c      Keeps version related info
compiler.h   include file to allow compiling with SDCC and GCC
Doxyfile     Control file for Source Documentation tool Doxygen
ds2756.c     Handle Maxim/Dallas DS2756
failsafe/    Failsafe Code
fs_entry.c   Trampoline for a bankswitching routine
kb3700.h     kb3700.h - header file for ENE KB3700 Keyboard Controler
main.c       Skeleton for the Embedded Controller of the OLPC project
Makefile.gcc Makefile for compiling with GCC
Makefile     SDCC Makefile
matrix_3x3.c Routines to handle 3x3 matrix within the OLPC project
openec.ctl   Control file for D52 disassembler    
port_0x6c.c  host communication routines for the EC of the OLPC
sfr_dump.c   dump register settings
sfr_rw.c     reading/writing mcs-51 sfr (special function registers)
states.c     Helps debugging state machines
timer.c      Timer routines for the Embedded Controller of the OLPC project
uart.c       handle serial IO on the EC
unused_irq.c Safe IRQ stubs for unused IRQ
watchdog.c   Watchdog of the EC

Status

Compilable, timer IRQ functional, blinks LEDs, decodes cursor keys, uart output functional (TX, no RX), dumps registers outputs (ec-dump.fth like) on boot and cursor key press, outputs status of internal state machines onto serial line. Reacts on Power button but does not power up the XO yet.

Status is tested on B1 but yet to be confirmed for others. Confirmed for B2

Desired Features

• Failsafe Code
• Easy debugging
• GCC compilable.

To Do

• lots