Embedded controller: Difference between revisions

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{{OLPC}}
{{Translations}}
{{Translations}}
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== Introduction ==
{{Olpcboxtop}}
{{OBX source dev|projects/openec}}
{{Olpcboxbottom}}
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[[Category:Firmware]]
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[[Category:SoC Project]]
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{{OLPC}}
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= Introduction =


The [[Hardware#XO_Laptop|XO-1 laptop]] uses a small micro-controller, an ENE KB3700 ([[Media:KB3700-ds-01.pdf|Datasheet]]), to control the battery charging operation and perform other tasks associated with starting and stopping the laptop.
OLPC is now working in an Open implementation of the XOs Embedded Controller.
The code of the EC is programed to a [[Image:KB3700-ds-01.pdf]] that has an 8051 microprocessor, for the code to be open we need to compile everything in [[SDCC]] or OFW.
The need for an open implementation is due to the fact that the actual EC has some flakiness in the recovery process.(among many other things).
An example of a bug of the old EC can be found in {{ticket|477}}


This Embedded Controller (EC) consists of a 8051 micro-controller, a dedicated LPC interface to communicate with the processor, and an SPI Flash ROM interface. The SPI Flash ROM supports two code segments, and a table of [[Manufacturing Data]]. The EC supports the Boot Hub Protocol, allowing the XO's main processor to boot from one of the code segments in the SPI Flash.


== Background ==
== Details ==


The EC is programed in the KB3700 and it has a paramount importance in controlling the XO when the CPU is not active.
The EC, implemented as a KB3700, has a paramount importance in controlling the XO when the CPU is not active. To do so, the KB3700 communicates with the CPU via the [[Revised_EC_Port_6C_Command_Protocol|EC protocol]] over a physical LPC interface. For more information, see the [[Ec specification]].

For doing so the KB3700 has to communicate with the CPU via the [[Revised_EC_Port_6C_Command_Protocol|EC protocol]], this protocol is managed in the ports 0x66 and 0x62 of the KB3700. These two ports are serially connected with the 0x6C and 0x68 ports of the CPU. (for more info check [[Ec_specification]]).
The KB3700 also communicates with the Maxim [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/5104 DS2756] battery fuel gauge IC within the battery pack, via the [http://en.wikipedia.org/wiki/1-Wire 1-wire] Dallas protocol. [[Media:DS2756.pdf|DS2756 data sheet]].
But the KB3700 has to communicate also with the DS2657 (The battery charger) via the 1 wire Dallas protocol.

One can deduce some of the inside programing of the EC via the [http://dev.laptop.org/~joel/ec-dump.fth ec-dump.fth] under OpenFirmware.
=== ec-status ===
Running the ec-dump script give us valuable data about internals of the ec, mostly the [[EC_Register_Settings]]
One can deduce part of the internal state of the EC using [http://dev.laptop.org/~joel/ec-dump.fth ec-dump.fth] under [[Open Firmware]]. Running the ec-dump script gives us valuable data about internals of the EC, being the [[EC Register Settings]].


The procedure to run '''ec-dump''' over internet in a wireless connection is:
The procedure to run '''ec-dump''' over internet in a wireless connection is:
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ok to-file u:\ec-dump fload http:\\18.85.2.147\~joel\ec-dump.fth
ok to-file u:\ec-dump fload http:\\18.85.2.147\~joel\ec-dump.fth


=== Forth tools ===
== Source and Licensing ==
For doing some of the ec work you might need the sdkit tools (sdkit permits that forth runs over linux) and also some other openfirmware code like
[http://dev.laptop.org/~wmb/spiflash.dic spiflash.dic]


The firmware running on the XO-1's EC, while heavily modified and supported by OLPC, was originally written by two different companies. OLPC had no success convincing those companies to open source their code.
=== Compiling from the host ===
first you have to git-clone the open ec code, then inside the openec file make


The OLPC community did work on [[OpenEC]], an Open Source implementation of the XO-1's Embedded Controller firmware. It reached an early stage and was not functional.
make -f Makefile.gcc


The XO-1.75 and XO-4 embedded controller firmware is open source. See [[Firmware]].
== Skeleton C implementation==


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== Related Documentation ==
*battery.c Skeleton for battery handling with the Embedded Controller (key)
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*Doxyfile Documentation file
*fs_entry.c Trampoline for a bankswitching routine
*Makefile.gcc Makefile per gcc
*port_0x6c.c host communication routines for the EC of the OLPC
*states.h Debugging state machine header
*uart.h Handle serial IO on the EC
*watchdog.h Handle watchdog of the EC
*battery.h Skeleton for battery handling with the Embedded Controller (key)
*ds2756.c Handle Maxim/Dallas DS2756
*kb3700.h kb3700.h - header file for ENE KB3700 Keyboard Controler
*matrix_3x3.c Routines to handle 3x3 matrix within the OLPC project
*port_0x6c.h Host communication routines for the EC of the OLPC
*timer.c Timer routines for the Embedded Controller of the OLPC project
*unused_irq.c Safe IRQ stubs for unused IRQ
*build.c Keeps version related info
*ds2756.h Handle Maxim/Dallas DS2756
*main.c Skeleton for the Embedded Controller of the OLPC project
*matrix_3x3.h Routines to handle 3x3 matrix within the OLPC project
*sfr_rw.c reading/writing mcs-51 sfr (special function registers)
*timer.h Timer routines for the Embedded Controler of the OLPC project
*unused_irq.h safe IRQ stubs for unused IRQ
*compiler.h SDCC compiler
*failsafe Failsafe Code.
*Makefile SDCC Makefile
*openec.ctl
*states.c Debugging state machine header
*uart.c handle serial IO on the EC
*watchdog.c Watchdog of the EC


*[[XO_Full_Reset|Rebooting the Embedded Controller in a laptop]]
= Actual development =
*[[Media:KB3700-ds-01.pdf|ENE KB3700 Datasheet]]

* See other articles in [[:Category:EC]]
All the work is going to be in the git repository [http://dev.laptop.org/git.do?p=projects/openec;a=summary OpenEC]

To get this code in your machine please do:
git-clone git://dev.laptop.org/projects/openec

''For info check [[Importing_your_project]]''

== Desired Features ==
* Failsafe Code
* Easy debugging
* Forth/C implementation.
* GCC compilable.

== To Do ==
* Testing

==Mail list==

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


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[[Category:Hardware]]
[[Category:Developers]]
[[Category:EC]]
[[Category:EC]]
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[[Category:Firmware]]

Latest revision as of 04:05, 13 August 2013

  This page is monitored by the OLPC team.
  english | español | 한국어 HowTo [ID# 291388]  +/-  

Introduction

The XO-1 laptop uses a small micro-controller, an ENE KB3700 (Datasheet), to control the battery charging operation and perform other tasks associated with starting and stopping the laptop.

This Embedded Controller (EC) consists of a 8051 micro-controller, a dedicated LPC interface to communicate with the processor, and an SPI Flash ROM interface. The SPI Flash ROM supports two code segments, and a table of Manufacturing Data. The EC supports the Boot Hub Protocol, allowing the XO's main processor to boot from one of the code segments in the SPI Flash.

Details

The EC, implemented as a KB3700, has a paramount importance in controlling the XO when the CPU is not active. To do so, the KB3700 communicates with the CPU via the EC protocol over a physical LPC interface. For more information, see the Ec specification.

The KB3700 also communicates with the Maxim DS2756 battery fuel gauge IC within the battery pack, via the 1-wire Dallas protocol. DS2756 data sheet.

ec-status

One can deduce part of the internal state of the EC using ec-dump.fth under Open Firmware. Running the ec-dump script gives us valuable data about internals of the EC, being the EC Register Settings.

The procedure to run ec-dump over internet in a wireless connection is: 

ok wifi media lab 802.11 *change it to your name AP
ok fl http:\\18.85.2.147\~joel\ec-dump.fth *change to your AP IP direction

Running ec-dump over internet and saving the file in a USB key: 

ok wifi media lab 802.11 *change it to your name AP
ok fload http:\\18.85.2.147\~rafael\to-file.fth
ok to-file u:\ec-dump fload http:\\18.85.2.147\~joel\ec-dump.fth

Source and Licensing

The firmware running on the XO-1's EC, while heavily modified and supported by OLPC, was originally written by two different companies. OLPC had no success convincing those companies to open source their code.

The OLPC community did work on OpenEC, an Open Source implementation of the XO-1's Embedded Controller firmware. It reached an early stage and was not functional.

The XO-1.75 and XO-4 embedded controller firmware is open source. See Firmware.

Related Documentation

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