Embedded controller: Difference between revisions
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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. |
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OLPC is now working in an Open implementation of the XOs Embedded Controller. |
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The code of the EC is programed to a KB3700 that has an 8051 microprocessor, for the code to be open we need to compile everything in [[SDCC]]. |
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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. |
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== Background == |
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== Details == |
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For that please see [http://dev.laptop.org/ticket/477 trac #477] |
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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]]. |
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= Actual development = |
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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]]. |
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All the work is going to be in the git repository [http://dev.laptop.org/git.do?p=projects/openec;a=summary] |
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== |
=== ec-status === |
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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]]. |
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The procedure to run '''ec-dump''' over internet in a wireless connection is: |
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* http://dev.laptop.org/~joel/ec-test.git/ |
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ok wifi media lab 802.11 *change it to your name AP |
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ok fl http:\\18.85.2.147\~joel\ec-dump.fth *change to your AP IP direction |
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Running '''ec-dump''' over internet and saving the file in a USB key: |
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To get this code in your machine please do: |
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ok wifi media lab 802.11 *change it to your name AP |
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git-clone http://dev.laptop.org/~joel/ec-test.git/ |
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ok fload http:\\18.85.2.147\~rafael\to-file.fth |
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ok to-file u:\ec-dump fload http:\\18.85.2.147\~joel\ec-dump.fth |
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== Source and Licensing == |
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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. |
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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. |
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The XO-1.75 and XO-4 embedded controller firmware is open source. See [[Firmware]]. |
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== Related Documentation == |
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*[[XO_Full_Reset|Rebooting the Embedded Controller in a laptop]] |
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*[[Media:KB3700-ds-01.pdf|ENE KB3700 Datasheet]] |
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* See other articles in [[:Category:EC]] |
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[[Category:Hardware]] |
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[[Category:Developers]] |
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[[Category:EC]] |
[[Category:EC]] |
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[[Category:Firmware]] |
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Latest revision as of 04:05, 13 August 2013
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
- Rebooting the Embedded Controller in a laptop
- ENE KB3700 Datasheet
- See other articles in Category:EC