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diff --git a/docs/ec_terms.md b/docs/ec_terms.md deleted file mode 100644 index 3b9f88416e..0000000000 --- a/docs/ec_terms.md +++ /dev/null @@ -1,248 +0,0 @@ -# EC Acronyms and Technologies - -## Glossary - -* **8042 Interface** {#8042} - - Interface for sending keyboard events to the [AP](#ap) and for receiving - commands from the AP. Only supported by x86 based APs. - -* **ACCEL - Accelerometer** {#accel} - - A sensor that measures acceleration, typically over 3-axis. Nominally - provides information about the orientation of a device. On Chromebook 2-in-1 - devices, there is an accelerometer in the base and one in the lid. Combining - the measurements from both accelerometers allows for a precise calculation - of the lid angle, used to switch between tablet and laptop mode. - -* **ACCELGYRO - Accelerometer/Gyroscope** {#accelgyro} - - A combination [accelerometer](#accel) and [gyroscope](#gyro) sensor that - provides more precise orientation information by measuring both linear and - rotational motion. - -* **ADC - Analog to Digital Converter** {#adc} - - A sensor that converts an analog voltage to a digital reading. - -* **ALS - Ambient Light Sensor** {#als} - - A sensor that measures the ambient light present. Used to automatically - control the screen and keyboard backlight level. - -* **AP - Application Processor** {#ap} - - The processor on the board that boots and runs ChromeOS. - -* **BAR - Barometer** {#bar} - - A sensor that measures atmospheric pressure. - -* **BC12 - Battery Charging** {#bc12} - - A device that implements the USB Battery Charging specification, version - 1.2. The complete [BC 1.2 Specification] is available from the USB - Implementers Forum. - -* **CBI - CROS Board Information** {#cbi} - - A collection of properties describing the board. This includes board - version, SKU, model name, and other fields. More details are found in the - [CrOS Board Info] documentation. - -* **CEC - Consumer Electronics Control** {#cec} - - A one-wire bidirectional bus. More details are on the [CEC Wikipedia page]. - -* **DPTF - Dynamic Power and Thermal Framework (Intel)** {#dptf} - - Intel's platform based power and thermal management. See the [DPTF Readme] - for details on the implementation used in ChromeOS. - -* **EC - Embedded Controller** {#ec} - - The [MCU](#mcu) used to control the keyboard, battery charging, USB port - switching, sensor management, and other functions, offloading these tasks - from the [AP](#ap). - -* **EC-3PO** {#ec-3po} - - A replacement of the current UART-based console which moves much of the code - off the EC into a host tool, reducing the amount of flash space required. - -* **E-Mark - Electronically Marked Cable** {#emark} - - See the [USB-C documentation](./usb-c.md#emark) for more details. - -* **eSPI - Enhanced Serial Peripheral Interface (Intel)** {#espi} - - Intel's synchronous communication interface between the [AP](#ap) and the - [EC](#ec). Supports quad I/O mode and clock speeds up to 66 Mhz, providing - bandwidth up to 264 Mbps. The full [eSPI Specification] is available from - Intel. - -* **FAFT - Fully Automated Firmware Tests** {#faft} - - A collection of tests and related infrastructure that exercise and verify - capabilities of Chrome OS. See the [FAFT design doc] and - [chromium.org documentation](https://www.chromium.org/for-testers/faft) for - more details. Replaced [SAFT](#saft). - -* **GMR - Giant Magnetoresistance Sensor** {#gmr} - - A sensor device that detects a magnetic field. These sensors differ from - [MAG](#mag) sensors, in that they only detect magnetic fields in close - proximity to the sensor. On Chromebooks, GMR sensors are used to detect when - the lid is opened. On convertible Chromebooks, the GMR sensor also detects - tablet mode when lid the is opened a full 360 degrees. - -* **GPIO - General Purpose Input/Output** {#gpio} - - An individual signal that can independently controlled and read. GPIOs are - used to enable/disable power rails, drive reset signals, and receive - interrupts from devices connected to the EC. GPIOs may also be connected to - [I/O expanders](#ioexpander). - -* **GYRO - Gyroscope** {#gyro} - - A sensor that measures angular momentum, providing information about - rotational motion of the device. - -* **I/O Expander** {#ioexpander} - - An [I2C](#i2c) peripheral device that provides additional GPIO signals - (anywhere from 8 - 32 signals). GPIOs behind an I/O expander are written and - read using I2C register accesses from the I2C controller in the EC. - -* **I2C - Inter-Integrated Circuit** {#i2c} - - A 2-wire synchronous communication bus, consisting of a clock signal and a - bidirectional data signal. An I2C bus typically contains one controller - device and one or more peripheral devices. The I2C standard defines - supported clock speeds of 100 KHz and 400 KHz. The full [I2C Specification] - is available from NXP (formerly Phillips). - -* **LED - Light Emitting Diode** {#led} - - A Light Emitting Diode is a semiconductor that emits light when current - flows through it. - -* **LPC - [Low Pin Count bus]** {#lpc} - - Legacy communication bus between the [AP](#ap) and [EC](#ec). Runs at 33 - MHz, providing a 133 Mbps bandwidth connection. Replaced by the - [eSPI](#espi) interface. - -* **MAG - Magnetometer** {#mag} - - A digital compass sensor, providing orientation for navigation. - -* **MCU - Microcontroller Unit** {#mcu} - - A small integrated chip containing a CPU core, on-chip ROM, on-chip RAM. - Also contains multiple peripheral interfaces, including GPIO, I2C buses, SPI - buses, ADC, PWM, etc. - -* **MKBP - Matrix Keyboard Protocol** {#mkbp} - - Message based protocol for communicating asynchronous events from the - [EC](#ec) to the [AP](#ap). Events are not limited to keyboard events with - the sensor subsystem as one of the main users. An EC board implementation - can be configured to send keyboard events through MKBP or using the - [8042 interface](#8042). This is the [EC MKBP driver] implementation. - -* **MST - Multi Stream Transport** {#mst} - - Part of the Display Port 1.2 standard, used to drive multiple independent - video streams from a single display port. The EC code is typically - responsible for enabling and disabling the MST hub chipset. - -* **OOBM - Out of Band Management** {#oobm} - - A command in the [EC-3PO protocol](#ec-3po) that allows commands to be - entered to alter the behaviour of the console and interpreter during - runtime. - -* **PD - USB Power Delivery** {#pd} - - See the [USB-C documentation](./usb-c.md#pd) for more details. - -* **PMIC - Power Management IC** {#pmic} - - An integrated circuit used to turn power rails on and off. - -* **PPC - USB Power Path Controller** {#ppc} - - See the [USB-C documentation](./usb-c.md#ppc) for more details. - -* **PWM - Pulse Width Modulation** {#pwm} - - Method of varying the duty cycle of a signal to control another device. A - typical application is to control fan speeds or the brightness of a - backlight. - -* **SAFT - Semi-Automated Firmware Tests** {#saft} - - A suite of tests for firmware, succeeded by [FAFT](#faft). See the - [chromium.org documentation](https://www.chromium.org/for-testers/saft) for - more details. - -* **SHI - SPI Host Interface** {#shi} - - [SPI](#spi) host interface used for communication between the AP and the EC. - In this configuration, the AP provides the SPI controller and the EC - provides the SPI peripheral. This interface is only used for non-x86 base - APs. - - x86-based APs use either the [eSPI](#espi) or [LPC](#lpc) interface. - -* **SPI - Serial Peripheral Interconnect** {#spi} - - A 4-wire synchronous communication bus consisting of the signals CLK - (clock), SDO (Serial Data Out), SDI (Serial Data In), and CS (chip-select, - one per SPI peripheral). The SDO and SDI pins are defined from the - perspective of the device: the SPI controller's SDO pin connects to the SPI - peripheral's SDI pin and vice-versa. Clock speeds over 100 MHz are - supported. SPI communication involves the following sequence: - - * SPI controller asserts CS. - * SPI controller transmits one or bytes on its SDO signal, received by the - SPI peripheral on its SDI signal. - * SPI peripheral transmits zero or more bytes on its SDO signal, received - by the SPI controller on its SDI signal. - * SPI controller de-asserts CS. - - The specific contents of a SPI frame varies based on the SPI peripheral - type. - -* **SVDM - Structured Vendor Defined Messages** {#svdm} - - See the [USB-C documentation](./usb-c.md#svdm) for more details. - -* **TCPC - USB Type-C Port Controller** {#tcpc} - - See the [USB-C documentation](./usb-c.md#tcpc) for more details. - -* **UART - Universal Asynchronous Receiver Transceiver** {#uart} - - Also known as a serial port. An asynchronous communication channel between - two devices with a dedicated receive pin, transmit pin, and ground. Optional - hardware flow control signals require additional connections between the - devices. Standard transmission rates are slow (up to 115200 bits per - second). Typical use is to provide a debug console to the EC. [RS-232] is - the protocol standard used by UARTs. - -* **VCONN - Connector Voltage** {#vconn} - - See the [USB-C documentation](./usb-c.md#vconn) for more details. - -[BC 1.2 Specification]: <https://www.usb.org/document-library/battery-charging-v12-spec-and-adopters-agreement> -[CrOS Board Info]: <https://chromium.googlesource.com/chromiumos/docs/+/HEAD/design_docs/cros_board_info.md> -[CEC Wikipedia page]: <https://en.wikipedia.org/wiki/Consumer_Electronics_Control> -[DPTF Readme]: <https://github.com/intel/dptf/blob/master/README.txt> -[eSPI Specification]: <https://www.intel.com/content/dam/support/us/en/documents/software/chipset-software/327432-004_espi_base_specification_rev1.0.pdf> -[FAFT design doc]: <https://chromium.googlesource.com/chromiumos/third_party/autotest/+/HEAD/docs/faft-design-doc.md> -[I2C Specification]: <https://www.nxp.com/docs/en/user-guide/UM10204.pdf> -[RS-232]: <https://en.wikipedia.org/wiki/RS-232> -[EC MKBP driver]: <https://chromium.googlesource.com/chromiumos/platform/ec/+/HEAD/common/keyboard_mkbp.c> -[Low Pin Count bus]: https://en.wikipedia.org/wiki/Low_Pin_Count |