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diff --git a/docs/ec_terms.md b/docs/ec_terms.md index 4f1b590b1a..7e3dadce86 100644 --- a/docs/ec_terms.md +++ b/docs/ec_terms.md @@ -1,12 +1,13 @@ # EC Acronyms and Technologies ## Glossary -* **8042 Interface**{#8042} + +* **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} +* **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 @@ -14,57 +15,57 @@ 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} +* **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} +* **ADC - Analog to Digital Converter** {#adc} A sensor that converts an analog voltage to a digital reading. -* **ALS - Ambient Light Sensor**{#als} +* **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} +* **AP - Application Processor** {#ap} The processor on the board that boots and runs ChromeOS. -* **BAR - Barometer**{#bar} +* **BAR - Barometer** {#bar} A sensor that measures atmospheric pressure. -* **BC12 - Battery Charging**{#bc12} +* **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} +* **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} +* **CEC - Consumer Electronics Control** {#cec} - A one-wire bidirectional bus. More details are on the [CEC Wikipedia page]. + A one-wire bidirectional bus. More details are on the [CEC Wikipedia page]. -* **DPTF - Dynamic Power and Thermal Framework (Intel)**{#dptf} +* **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} +* **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} +* **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. @@ -73,47 +74,47 @@ See the [USB-C documentation](./usb-c.md#emark) for more details. -* **eSPI - Enhanced Serial Peripheral Interface (Intel)**{#espi} +* **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} +* **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). + 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 + 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} +* **GPIO - General Purpose Input/Output** {#gpio} - An individual signal that can independently controlled and read. GPIOs are + 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). + interrupts from devices connected to the EC. GPIOs may also be connected to + [I/O expanders](#ioexpander). -* **GYRO - Gyroscope**{#gyro} +* **GYRO - Gyroscope** {#gyro} A sensor that measures angular momentum, providing information about rotational motion of the device. -* **I/O Expander**{#ioexpander} +* **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. + (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} +* **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 @@ -121,101 +122,101 @@ supported clock speeds of 100 KHz and 400 KHz. The full [I2C Specification] is available from NXP (formerly Phillips). -* **LED - Light Emitting Diode**{#led} +* **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} +* **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 + MHz, providing a 133 Mbps bandwidth connection. Replaced by the [eSPI](#espi) interface. -* **MAG - Magnetometer**{#mag} +* **MAG - Magnetometer** {#mag} A digital compass sensor, providing orientation for navigation. -* **MCU - Microcontroller Unit**{#mcu} +* **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} +* **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. + 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} +* **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} +* **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} +* **PD - USB Power Delivery** {#pd} See the [USB-C documentation](./usb-c.md#pd) for more details. -* **PMIC - Power Management IC**{#pmic} +* **PMIC - Power Management IC** {#pmic} An integrated circuit used to turn power rails on and off. -* **PPC - USB Power Path Controller**{#ppc} +* **PPC - USB Power Path Controller** {#ppc} See the [USB-C documentation](./usb-c.md#ppc) for more details. -* **PWM - Pulse Width Modulation**{#pwm} +* **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} +* **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. -* **SPI - Serial Peripheral Interconnect**{#spi} +* **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 + 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. + * 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} +* **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} +* **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} +* **UART - Universal Asynchronous Receiver Transceiver** {#uart} - Also known as a serial port. An asynchronous communication channel between + 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 @@ -226,7 +227,6 @@ 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/+/master/design_docs/cros_board_info.md> [CEC Wikipedia page]: <https://en.wikipedia.org/wiki/Consumer_Electronics_Control> |