Commit graph

1064 commits

Author SHA1 Message Date
Benoît Thébaudeau 621f4f7339 cc2538: lpm: Give access to the SRAM non-retention area for PM2
If PM2 is enabled with LPM_CONF_MAX_PM, but not active, the non-retention area
of the SRAM can be useful to place temporary data that does not fit in the
low-leakage SRAM, typically after having called lpm_set_max_pm(LPM_PM1). Hence,
give access to this non-retention area thanks to .nrdata* sections.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-25 15:43:37 +01:00
Benoît Thébaudeau 270ed237fd cc2538: usb: Make the GPIO driving the pull-up optional
The data sheet recommends that the USB pull-up resistor be driven by a GPIO so
that it can be controlled by software, but this is not mandatory. Hence, leave
the choice so that CC253-based boards not using this option can build and work
fine.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-25 15:15:35 +01:00
Benoît Thébaudeau d2f3795a30 cc2538: Clean up port and pin definitions
Homogenize port and pin definitions naming:
 - PERIPHERAL_FUNCTION_PORT for the port ID,
 - PERIPHERAL_FUNCTION_PIN for the pin ID,
 - PERIPHERAL_FUNCTION_PORT_BASE for the port base,
 - PERIPHERAL_FUNCTION_PIN_MASK for the pin mask.

Define only PERIPHERAL_FUNCTION_PORT and PERIPHERAL_FUNCTION_PIN in board.h, and
deduce PERIPHERAL_FUNCTION_PORT_BASE and PERIPHERAL_FUNCTION_PIN_MASK in the
driver from the former definitions.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-25 15:00:41 +01:00
Adam Dunkels bb2dcaa057 A massive all-tree automated update of all double inclusion guard #defines that changes from using two underscores as a prefix, which are reserved, to not using two underscores as a prefix 2013-11-24 20:20:11 +01:00
Adam Dunkels e09ff3ff1e Merge pull request #438 from adamdunkels/push/cleanup-platforms
Massive platform cleanup
2013-11-24 01:59:53 -08:00
Adam Dunkels 1ab28e4668 Added missing argument declaration 2013-11-23 15:05:16 +01:00
Adam Dunkels e95236b642 Added header declarations for cc2538_rf_read_rssi() and cc2538_rf_set_promiscous_mode() 2013-11-23 15:05:16 +01:00
Adam Dunkels 76f2a10c9a Added a function for setting promiscous mode on the CC2538 RF core 2013-11-23 15:05:15 +01:00
Adam Dunkels 473d519926 Added a way to obtain the RSSI from the CC2538 RF core 2013-11-23 15:05:15 +01:00
Adam Dunkels 27433244a9 The pc-6001 platform was the last z80 platform in the tree, so we'll remove the cpu/z80 directory too 2013-11-22 16:33:46 +01:00
Adam Dunkels 7a310935d8 An implementation of the mc1322x watchdog 2013-11-22 15:54:06 +01:00
Adam Dunkels 88f9d79053 Enable the silent compilation mode from the latest Contiki 2013-11-22 15:53:30 +01:00
Oliver Schmidt 737d5fd6dc Replaced web configurator with target-based ethconfig. 2013-11-21 21:57:42 +01:00
Oliver Schmidt 3abd5d3d8d Show current IP config on startup. 2013-11-20 22:33:11 +01:00
George Oikonomou f13af20f12 Merge pull request #409 from ADVANSEE/cc2538-spi
cc2538: spi: Bug fix and various improvements
2013-11-20 06:51:26 -08:00
Benoît Thébaudeau e8a8870d1d cc2538: spi: Add enable and disable functions
This makes it possible to reduce the power consumption when the SPI is unused.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-20 14:20:50 +01:00
Benoît Thébaudeau b134e35450 cc2538: spi: Add format configuration options
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-20 14:20:43 +01:00
Nicolas Tsiftes 263e212427 Merge pull request #431 from adamdunkels/push/ipv6-const
Make IP addresses const
2013-11-20 04:26:05 -08:00
Nicolas Tsiftes d183b87f4b Merge pull request #434 from adamdunkels/push/cleanup-sys
Remove old unused code from the core/sys/ directory
2013-11-19 09:53:57 -08:00
George Oikonomou dc05eea3f5 Merge pull request #426 from ADVANSEE/cc2538-rom
cc2538: Add driver for the rom utility function library
2013-11-19 03:09:16 -08:00
Adam Dunkels 30c0c5eaf6 Removed old unused timetable code 2013-11-19 08:29:23 +01:00
Adam Dunkels 469884171a Added the const keyword to functions that use the tcpip_set_outputfunc(), which now takes a const argument 2013-11-18 23:26:37 +01:00
Benoît Thébaudeau 1f1b940cb9 cc2538: Add driver for the rom utility function library
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-18 12:38:06 +01:00
Benoît Thébaudeau 035a30602b cc2538: lpm: Make periph_permit_pm1_funcs static
periph_permit_pm1_funcs[] is a private member of lpm.c, so define it as static.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-18 11:57:59 +01:00
George Oikonomou b10c78f854 Merge pull request #425 from ADVANSEE/cc2538-gpio
cc2538: gpio: Bug fix and various improvements
2013-11-15 13:04:09 -08:00
George Oikonomou 98a1f2dfa9 Merge pull request #408 from ADVANSEE/cc2538-uart
cc2538: lpm: Add registration mechanism for peripherals and use it
2013-11-15 12:57:03 -08:00
Benoît Thébaudeau 680050861c cc2538: gpio: Use accessor macros
Use the GPIO accessor macros instead of copying raw register access code all
over the place. This is cleaner and less error prone.

This fixes the setting of the USB pull-up resistor that worked only by chance on
the CC2538DK because it is controlled by the pin 0 of the used GPIO port.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 19:57:44 +01:00
Benoît Thébaudeau 923f161b7b cc2538: gpio: Add pin read / write and interrupt clear macros
Introduce new useful GPIO macros to:
 - read the levels of some port pins,
 - write the levels of some port pins (pass bit-field value to be set),
 - clear the interrupt flags for some port pins.

These macros are cleaner and less error prone than raw register access code
copied all over the place.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 19:48:24 +01:00
Benoît Thébaudeau 300d2d79ae cc2538: gpio: Fix usage of parameters in macros
The parameters in the GPIO macros were used without being parenthesized. This
could generate wrong values for register assignments in the case of expressions
passed as arguments to these macros.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 19:43:06 +01:00
Benoît Thébaudeau b8b54a033c cc2538: uart: Fix crippled output occurring upon lpm_enter()
lpm_enter() must not enter PM1+ if the UART TX FIFO is not empty. Otherwise, the
UART clock gets disabled, and its TX is broken.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 17:24:26 +01:00
Benoît Thébaudeau 0692ee251d cc2538: usb: Use the new LPM peripheral registration
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 17:14:45 +01:00
Benoît Thébaudeau d35732505b cc2538: lpm: Add registration mechanism for peripherals
Some peripherals have their clocks automatically gated in PM1+ modes, so they
cannot operate. This new mechanism gives peripherals a way to prohibit PM1+
modes so that they can properly complete their current operations before
entering PM1+.

This mechanism is implemented with peripheral functions registered to the LPM
module. These functions return whether the associated peripheral permits or not
PM1+ modes. They are called by the LPM module each time PM1+ might be possible.
If any of the peripherals wants to block PM1+, then the system is only dropped
to PM0.

Partly from: George Oikonomou
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 17:09:22 +01:00
George Oikonomou d08a87880c Merge pull request #410 from ADVANSEE/cc2538-sys_ctrl
cc2538: sys_ctrl: Make it possible to use the 32-kHz crystal
2013-11-15 07:42:45 -08:00
Benoît Thébaudeau f1ca1b742c cc2538: spi: Include spi-arch.h before dev/spi.h
spi-arch.h configures dev/spi.h, so it must be #included first. Luckily, this
mistake did not have any consequence here, but fix it in order to avoid possible
future issues.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 15:56:40 +01:00
Benoît Thébaudeau f34731c1a9 cc2538: spi: Do not call SPI_WAITFOREORx() at end of init
If the SSI has never been used and spi_init() is called, then the SSI receive
FIFO is empty and remains so, so calling SPI_WAITFOREORx() at the end of
spi_init() waits endlessly for SSI_SR.RNE to be set. Hence, this call must be
removed in order to avoid a deadlock.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 15:56:40 +01:00
Benoît Thébaudeau 47d570343e cc2538: sys_ctrl: Make it possible to use the 32-kHz crystal
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 15:52:10 +01:00
Benoît Thébaudeau a7d10ce2ad cc2538: Make it possible to use a custom linker script
Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 15:41:58 +01:00
Benoît Thébaudeau 974850cdf2 cc2538: Generate .hex output
ELF files generated by GCC make SmartRF Flash Programmer 2 crash (only the TI
format is supported by this tool for ELFs), and binary files are not very
appropriate because they are gapless, so generate Intel HEX files since these
are very well supported by most programming tools while still flexible.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
2013-11-15 15:41:58 +01:00
Mariano Alvira 6b9b457a60 Merge pull request #385 from ismb-pert/better-error-message
Better error message in case of wrong CPUREV value
2013-11-14 07:14:33 -08:00
Oliver Schmidt 59c28bc32b Merge pull request #419 from oliverschmidt/master
Saved six more bytes ;-)
2013-11-13 14:43:06 -08:00
Oliver Schmidt 1bf5b4380d Saved six more bytes ;-) 2013-11-13 23:32:49 +01:00
Oliver Schmidt 497e7fbbac Merge pull request #416 from oliverschmidt/master
Added missing fixup & removed wait loop from poll.
2013-11-11 12:06:38 -08:00
Oliver Schmidt ae1a875881 Added missing fixup & removed wait loop from poll. 2013-11-11 21:03:39 +01:00
Oliver Schmidt dd30454c80 Merge pull request #415 from oliverschmidt/master
Added 6502 driver for WIZnet W5100 in MACRAW mode.
2013-11-09 14:17:07 -08:00
Oliver Schmidt 2d7d1b123d Added 6502 driver for WIZnet W5100 in MACRAW mode. 2013-11-09 23:15:20 +01:00
George Oikonomou ce0b2cacac Merge pull request #365 from g-oikonomou/cc2538-uart-init-fix
Set peripheral mode for the correct CC2538 UART TX/RX pins
2013-10-23 07:10:41 -07:00
Gianfranco Costamagna ddd6b900cd Better error message in case of wrong CPUREV value 2013-10-17 12:33:36 +02:00
Oliver Schmidt 57d9c43a33 Removed support for 'atari' now that 'atarixl' is part of the cc65 master. 2013-10-03 22:55:32 +02:00
Oliver Schmidt 7c2f3b3911 Saved another byte ;-) 2013-10-03 22:32:12 +02:00
George Oikonomou e4a454b284 Set peripheral mode for the correct UART TX/RX pins 2013-09-30 14:50:39 +01:00
George Oikonomou 2957d44ff8 Merge pull request #352 from lab11/cc2538-spi-driver
Added SPI driver for CC2538
2013-09-28 13:25:17 -07:00
Brad Campbell e2af903d05 Added SPI driver for CC2538
This uses the core/dev/spi.h header and implements the spi_init()
function and the various macros for SPI operation. ssi.h contains all of
the register locations and information.

This implementation is not very versatile, mostly because I don't how to
make it flexible in the contiki system. It supports pin muxing for the
four spi pins, but other than that picks sensible defaults.

The SPI macros (like SPI_READ()) are defined in
cpu/cc2538/spi-arch.h. In order to use the SPI driver, add the following
includes to your project:

    #include "spi-arch.h
    #include "dev/spi.h"
2013-09-27 17:46:15 -04:00
Oliver Schmidt 2263c1aa55 - Optimized LAN91C96 driver for speed and size.
- Speed: The primary byte copy loops are reduzed to the bare minimum by adjusting the base pointer 'ptr' and loop register 'y' in such a way that the 'y' overflow matches the low byte of the loop size.

- Introduced a loop for setting the MAC address.

Additional minor fix:

- Properly start self modification with first location.
2013-09-12 23:32:26 +02:00
Oliver Schmidt ea08635ca4 Optimized CS8900A driver for speed and size.
- Speed: The primary byte copy loops are reduzed to the bare minimum by adjusting the base pointer 'ptr' and loop register 'y' in such a way that the 'y' overflow matches the low byte of the loop size.

- Size: Factored out all repeated code into subroutines. Introduced a loop for setting the MAC address.

Additional minor changes:

- Activate frame reception as last step of initialization after CS8900A configuration.

- Properly set internal address bits used by the CS8900A.
2013-09-12 23:32:25 +02:00
Brad Campbell 982ca0fb46 Updates CC2538 GPIO
1. Fixes two of the comments to GPIO macros. They were copied but not
updated.
2. Adds SET and CLR macros for controlling GPIO pins.
2013-09-11 21:39:56 -04:00
Nicolas Tsiftes 7987a6dac7 Merge pull request #328 from g-oikonomou/cc2538-uart-config
Make the CC2538 UART driver more configurable
2013-08-09 10:20:36 -07:00
George Oikonomou 460d5bcb5d Fix cc2530 UART1 init bug
Fixes #286
2013-08-09 16:09:12 +01:00
George Oikonomou cb075dec65 Disable SDCC warnings 110 and 126
Those two warnings are optimisation-related
* 110 warns that an always-false if branch has been optimised out
* 126 warns about unreachable code which also gets optimised out

In disabling those warnings, we make the build less cluttered
2013-08-09 15:57:49 +01:00
George Oikonomou 20f06e3271 Support verbosity control for 8051-based platforms 2013-08-09 15:57:21 +01:00
George Oikonomou c89450a233 Change to sdar from the now deprecated sdcclib 2013-08-09 15:56:16 +01:00
George Oikonomou b025759665 Don't redirect sdld output to dev/null
This was used in the past because sdld was
very verbose when linking banked hex files. New
sdld versions do not exhibit this level of
verbosity and therefore the redirect can be
stopped
2013-08-09 15:56:15 +01:00
George Oikonomou 1b0470687b Change the cc2531 usb stick descriptor
The CC2531 USB stick now identifies itself as a
'Texas Instruments CC2531 USB Dongle' and uses a
TI-assigmed VID:PID. The VID:PID is now configurable
in contiki- or project-conf.h
2013-08-09 15:51:58 +01:00
George Oikonomou 0a7094bc39 Remove leftover make targets
The sensinode platform does not support .upload and .serialdump
Their presence in the makefile has confused in the past confused
some users. This commit removes them

The commit also removes the $(OBJECTDIR)/%.rel: %.cS recipe which
is not used by either 8051 platform and is probably broken anyway,
since it has been unmaintained for years
2013-08-09 15:48:05 +01:00
George Oikonomou 6c6013b898 Make the CC2538 UART driver more configurable
* We can now very easily switch between UART0 and UART1 through a define
* We can also configure the UART RX and TX port/pin through defines
2013-08-09 12:20:25 +01:00
George Oikonomou c3b5d4f5e3 Add support for verbosity control 2013-08-07 15:26:22 +01:00
Nicolas Tsiftes a9f0907640 Merge pull request #304 from frtos-wpan/rf230bb-merged
cpu/avr/radio/rf230bb/rf230bb.c (rf230_transmit): extend comment on tx s...
2013-08-05 00:24:35 -07:00
Oliver Schmidt 6ab336f55f Several minor consistency improvements. 2013-07-31 00:55:31 +02:00
Oliver Schmidt 3c6c7381d8 Suppress some usual warnings. 2013-07-31 00:29:52 +02:00
Oliver Schmidt 8d23d1b0bb Support the recently added verbosity control. 2013-07-31 00:15:38 +02:00
Oliver Schmidt 116c3f119b unistd.h doesn't seem to be necessary but breaks the MS VC build. 2013-07-31 00:02:29 +02:00
Werner Almesberger be0a296049 cpu/avr/radio/rf230bb/rf230bb.c (rf230_transmit): extend comment on tx sequence
Explain that the transmission is intentionally started before copying the
frame to the buffer.
2013-07-28 18:43:29 -03:00
Mariano Alvira 5d19de3dbf Merge pull request #266 from ismb-pert/fix-mbxxx
mb851 platform is now the more generic mbxxx. STM32W_CPUREV environment variable is used to select the variant of STM32W to use.
2013-07-26 07:38:11 -07:00
stefano pascali 36e7db42de Some little refactor 2013-07-19 16:15:55 +02:00
stefano pascali b43ce0f677 Travis-ci tweaks, added CPUREV to 01 regression test, needed by mbxxx platform 2013-07-12 17:07:04 +02:00
stefano pascali fcb09d5d30 Fixed mbxxx platform 2013-07-11 17:56:17 +02:00
Mariano Alvira 6307f3ff95 mc1322x: make uart buffer sizes configurable from contiki-conf.h 2013-07-04 14:09:40 -04:00
Oliver Schmidt ad34b714cd Merge pull request #287 from oliverschmidt/master
The current cc65 build doesn't require this workaround anymore.
2013-06-27 15:38:48 -07:00
Oliver Schmidt fb1de74dc4 The current cc65 build doesn't require this workaround anymore. 2013-06-28 00:36:33 +02:00
Peter A. Bigot 5fc0575e99 Makefile.include: support make clean all
Historically $(OBJECTDIR) was created when Makefile.include is read.  A
consequence is that combining "clean" with "all" (or any other build
target) results in an error because the clean removes the object
directory that is required to exist when building dependencies.
Creating $(OBJECTDIR) on-demand ensures it is present when needed.

Removed creation of $(OBJECTDIR) on initial read, and added an order-only
dependency forcing its creation all Makefile* rules where the target is
explicitly or implicitly in $(OBJECTDIR).
2013-06-20 17:45:41 -05:00
Oliver Schmidt 79bb5ea73f Removed some more old RCS tags from the Contiki source tree. 2013-06-13 15:54:26 +02:00
Oliver Schmidt cbce31cb59 Another small addition for platform 'Atari XL'. 2013-06-02 23:36:28 +02:00
Robert Quattlebaum 36fbbe48aa Merge pull request #244 from darconeous/pull-requests/cpu-native-tapdev-ipv6-fix
native/net/tapdev: Fix for new `UIP_CONF_IPV6` handling.
2013-05-21 17:42:44 -07:00
Nicolas Tsiftes a445c4020d Merge pull request #153 from darconeous/pull-requests/cpu-avr-bootloader
avr/bootloader.c: Now compatible with bootloaders which always run first
2013-05-20 05:49:13 -07:00
Robert Quattlebaum 09eec82d08 Merge pull request #134 from darconeous/pull-requests/cpu-avr-avrdude-mcu
cpu/avr: Added "AVRDUDE_MCU" configuration parameter.
2013-05-19 17:35:26 -07:00
Robert Quattlebaum 9c70e0e5cc native/net/tapdev: Fix for new UIP_CONF_IPV6 handling. 2013-05-19 17:27:30 -07:00
Robert Quattlebaum 674f70b6c3 cpu/avr: Added "AVRDUDE_MCU" configuration parameter. 2013-05-19 14:23:31 -07:00
Adam Dunkels aaac20a950 Merge pull request #225 from tecip-nes/pic32_minor_reorganization
Pic32 minor reorganization
2013-05-19 14:22:14 -07:00
Robert Quattlebaum 9c17a542a7 avr/bootloader.c: Now compatible with bootloaders which always run first.
The boot loader now knows when to go into bootstrap mode by
looking for a specific EEPROM value. Also updated code style
to match Contiki code style guidelines.
2013-05-19 08:21:16 -07:00
Robert Quattlebaum 535e90343c Merge pull request #144 from darconeous/pull-requests/settings-for-all-targets
core/lib/settings: Generalized settings manager to work on any platform
2013-05-18 12:03:09 -07:00
Robert Quattlebaum b8c0f2de6c cpu/native: Add file-backed simulated EEPROM to native cpu.
This patch removes a defunct EEPROM implementation from the native
platform and provides a new EEPROM implementation for the native cpu.
The previous implementation appears to be vestigal.

This is useful for testing code which uses the EEPROM without running
the code on the actual hardware.

By default the code will create a new temporary file as the EEPROM
backing, reinitializing each time. If you would like to preserve the
EEPROM contents or specify a specific EEPROM file to use, you can set the
`CONTIKI_EEPROM` environment variable to the name of the EEPROM file you
wish to use instead. If it already exists, its contents will be used.
If it does not already exist, it will be created and initialized by
filling it with `0xFF`---just like a real EEPROM.

A new example is also included, which was used to verify the correctness
of the implementation. It can easily be used to verify the EEPROM
implementations of other targets.
2013-05-18 10:29:41 -07:00
Giovanni evilaliv3 Pellerano c33d51e762 pic32 minor cleanups 2013-05-17 14:32:39 +02:00
Adam Dunkels 59a8df14a8 Merge pull request #189 from sieben/markdown
Update to markdown
2013-05-16 00:24:25 -07:00
François Revol 7967779e6c tapdev: Fix using an uninitialized buffer 2013-04-20 14:42:19 +02:00
George Oikonomou 704309cfd4 Change the InfoPage Location of the IEEE address 2013-04-17 15:44:01 +01:00
George Oikonomou 8b5b2bd4d8 CC2538 Documentation typo and grammar fixes 2013-04-17 15:41:41 +01:00
George Oikonomou 007e113ea9 Improve handling of CDC ACM line state
- For the CC2538, simplify handling of USB_CDC_ACM_LINE_STATE
  events. Ignore the Carrier Control (RTS) bit when receiving
  a SET_CONTROL_LINE _STATE request, we are a full duplex device.
- Improve behaviour of the CC2531 USB stick when there is no
  process on the host to read IN data. Basically, we adopt the
  CC2538 approach and we only send data when a DTE is present
2013-04-16 15:49:05 +01:00
George Oikonomou 40f49948e6 New Platform: TI CC2538 Development Kit
This commit adds cpu, platform and example files,
providing support for running Contiki on TI's cc2538 DK
2013-04-06 21:07:31 +01:00
Rémy Léone e6bd4f1dde Rename to md 2013-03-26 23:15:37 +01:00
Rémy Léone 7b40a568a6 Update to markdown
- Spellchecking
- Update plain text to github markdown
2013-03-26 16:55:19 +01:00
Robert Quattlebaum 28a1e40ebd core/lib/settings: Generalized Settings Manager to work on any platform
This commit moves the Settings Manager from the AVR codebase
into the Contiki core library. Any platform that implements
the Contiki EEPROM API can now use the Settings Manager's
key-value store for storing their persistent configuration info.

The Settings Manager is a EEPROM-based key-value store. Keys
are 16-bit integers and values may be up to 16,383 bytes long.
It is intended to be used to store configuration-related information,
like network settings, radio channels, etc.

 * Robust data format which requires no initialization.
 * Supports multiple values with the same key.
 * Data can be appended without erasing EEPROM.
 * Max size of settings data can be easily increased in the future,
   as long as it doesn't overlap with application data.

The format was inspired by the [OLPC manufacturing data format][].

Since the beginning of EEPROM often contains application-specific
information, the best place to store settings is at the end of EEPROM
(the "top"). Because we are starting at the end of EEPROM, it makes
sense to grow the list of key-value pairs downward, toward the start of
EEPROM.

Each key-value pair is stored in memory in the following format:

Order    | Size     | Name         | Description
--------:|---------:|--------------|-------------------------------
       0 |        2 | `key`        | 16-bit key
      -2 |        1 | `size_check` | One's-complement of next byte
      -3 |   1 or 2 | `size`       | The size of `value`, in bytes
-4 or -5 | variable | `value`      | Value associated with `key`

The end of the key-value pairs is denoted by the first invalid entry.
An invalid entry has any of the following attributes:

 * The `size_check` byte doesn't match the one's compliment of the
   `size` byte (or `size_low` byte).
 * The key has a value of 0x0000.

[OLPC manufacturing data format]: http://wiki.laptop.org/go/Manufacturing_data
2013-03-20 11:57:13 -07:00