Documentation
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Overview ¶
Package chip contains header definitions for NextThing Co's C.H.I.P. board.
CHIP uses the Allwinner R8 processor and thus the allwinner host package is automatically imported.
This package exports the U13 header, which is opposite the power LED, and U14, which is right next to the power LED. Most of the pins are usable as GPIO and are directly to the processor. These can use memory-mapped GPIO, which is very fast. The XIO-P0 through XIO-P7 pins are attached to a pcf8574 I²C expander which has the result that all accesses to these pins have to go through the kernel and the I²C bus protocol, i.e., they're slow.
GPIO edge detection (using interrupts) is only supported on a few of the processor's pins: AP-EINT1, AP-EINT3, CSIPCK, and CSICK. Edge detection is also supported on the XIO pins, but this feature is rather limited due to the device and the driver (for example, the driver interrupts on all edges).
References ¶
http://www.chip-community.org/index.php/Hardware_Information
http://docs.getchip.com/chip.html#chip-hardware
A graphical view of the board headers is available at: http://docs.getchip.com/chip.html#pin-headers
Index ¶
Constants ¶
This section is empty.
Variables ¶
var ( TEMP_SENSOR = &pin.BasicPin{N: "TEMP_SENSOR"} PWR_SWITCH = &pin.BasicPin{N: "PWR_SWITCH"} // XIO "gpio" pins attached to the pcf8574 I²C port extender. XIO0, XIO1, XIO2, XIO3, XIO4, XIO5, XIO6, XIO7 gpio.PinIO )
C.H.I.P. hardware pins.
var ( U13_1 = pin.GROUND // U13_2 = pin.DC_IN // U13_3 = pin.V5 // (filtered) U13_4 = pin.GROUND // U13_5 = pin.V3_3 // U13_6 = TEMP_SENSOR // Analog temp sensor input U13_7 = pin.V1_8 // U13_8 = pin.BAT_PLUS // External LiPo battery U13_9 = allwinner.PB16 // I2C1_SDA U13_10 = PWR_SWITCH // Power button U13_11 = allwinner.PB15 // I2C1_SCL U13_12 = pin.GROUND // U13_13 = allwinner.X1 // Touch screen X1 U13_14 = allwinner.X2 // Touch screen X2 U13_15 = allwinner.Y1 // Touch screen Y1 U13_16 = allwinner.Y2 // Touch screen Y2 U13_17 = allwinner.PD2 // LCD-D2; UART2_TX firmware probe for 1-wire to detect DIP at boot; http://docs.getchip.com/dip.html#dip-identification U13_18 = allwinner.PB2 // PWM0; EINT16 U13_19 = allwinner.PD4 // LCD-D4; UART2_CTS U13_20 = allwinner.PD3 // LCD-D3; UART2_RX U13_21 = allwinner.PD6 // LCD-D6 U13_22 = allwinner.PD5 // LCD-D5 U13_23 = allwinner.PD10 // LCD-D10 U13_24 = allwinner.PD7 // LCD-D7 U13_25 = allwinner.PD12 // LCD-D12 U13_26 = allwinner.PD11 // LCD-D11 U13_27 = allwinner.PD14 // LCD-D14 U13_28 = allwinner.PD13 // LCD-D13 U13_29 = allwinner.PD18 // LCD-D18 U13_30 = allwinner.PD15 // LCD-D15 U13_31 = allwinner.PD20 // LCD-D20 U13_32 = allwinner.PD19 // LCD-D19 U13_33 = allwinner.PD22 // LCD-D22 U13_34 = allwinner.PD21 // LCD-D21 U13_35 = allwinner.PD24 // LCD-CLK U13_36 = allwinner.PD23 // LCD-D23 U13_37 = allwinner.PD26 // LCD-VSYNC U13_38 = allwinner.PD27 // LCD-HSYNC U13_39 = pin.GROUND // U13_40 = allwinner.PD25 // LCD-DE: RGB666 data )
The U13 header is opposite the power LED.
The alternate pin functionality is described at pages 322-323 of https://github.com/NextThingCo/CHIP-Hardware/raw/master/CHIP%5Bv1_0%5D/CHIPv1_0-BOM-Datasheets/Allwinner%20R8%20User%20Manual%20V1.1.pdf
var ( U14_1 = pin.GROUND // U14_2 = pin.V5 // (filtered) U14_3 = allwinner.PG3 // UART1_TX; EINT3 U14_4 = allwinner.HP_LEFT // Headphone left output U14_5 = allwinner.PG4 // UART1_RX; EINT4 U14_6 = allwinner.HP_COM // Headphone amp out U14_7 = allwinner.FEL // Boot mode selection U14_8 = allwinner.HP_RIGHT // Headphone right output U14_9 = pin.V3_3 // U14_10 = allwinner.MIC_GND // Microphone ground U14_11 = allwinner.KEY_ADC // LRADC Low res analog to digital U14_12 = allwinner.MIC_IN // Microphone input U14_13 = XIO0 // gpio via I²C controller U14_14 = XIO1 // gpio via I²C controller U14_15 = XIO2 // gpio via I²C controller U14_16 = XIO3 // gpio via I²C controller U14_17 = XIO4 // gpio via I²C controller U14_18 = XIO5 // gpio via I²C controller U14_19 = XIO6 // gpio via I²C controller U14_20 = XIO7 // gpio via I²C controller U14_21 = pin.GROUND // U14_22 = pin.GROUND // U14_23 = allwinner.PG1 // GPS_CLK; AP-EINT1 U14_24 = allwinner.PB3 // IR_TX; AP-EINT3 (EINT17) U14_25 = allwinner.PB18 // I2C2_SDA U14_26 = allwinner.PB17 // I2C2_SCL U14_27 = allwinner.PE0 // CSIPCK: CMOS serial interface; SPI2_CS0; EINT14 U14_28 = allwinner.PE1 // CSICK: CMOS serial interface; SPI2_CLK; EINT15 U14_29 = allwinner.PE2 // CSIHSYNC; SPI2_MOSI U14_30 = allwinner.PE3 // CSIVSYNC; SPI2_MISO U14_31 = allwinner.PE4 // CSID0 U14_32 = allwinner.PE5 // CSID1 U14_33 = allwinner.PE6 // CSID2 U14_34 = allwinner.PE7 // CSID3 U14_35 = allwinner.PE8 // CSID4 U14_36 = allwinner.PE9 // CSID5 U14_37 = allwinner.PE10 // CSID6; UART1_RX U14_38 = allwinner.PE11 // CSID7; UART1_TX U14_39 = pin.GROUND // U14_40 = pin.GROUND // )
The U14 header is right next to the power LED.
Functions ¶
func Present ¶
func Present() bool
Present returns true if running on a NextThing Co's C.H.I.P. board.
It looks for "C.H.I.P" in the device tree. The following information is expected in the device dtree:
root@chip2:/proc/device-tree# od -c compatible 0000000 n e x t t h i n g , c h i p \0 a 0000020 l l w i n n e r , s u n 5 i - r 0000040 8 \0 root@chip2:/proc/device-tree# od -c model 0000000 N e x t T h i n g C . H . I . 0000020 P . \0
Types ¶
This section is empty.
Source Files
Directories
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Package chipsmoketest is leveraged by periph-smoketest to verify that basic CHIP specific functionality works.
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Package chipsmoketest is leveraged by periph-smoketest to verify that basic CHIP specific functionality works. |