book

Raspberry Pi Hardware Reference

by Warren W. Gay

November 2014

Beginner to intermediate

248 pages

4h 40m

English

Apress

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ModelsHardware in CommonWhich Model?
Calculating PowerCurrent RequirementPeripheral PowerModel B Input PowerModel A Input Power3.3 Volt PowerPowered USB HubsPower AdaptersAn Unsuitable SupplyE-book AdaptersBest Power SourceVoltage TestBattery PowerRequirementsHeadroomLM7805 RegulationDC-DC Buck ConverterSigns of Insufficient PowerNo Power
Status LEDsOK or ACT LEDPWR LEDFDX LEDLNK LED10M or 10/100 LEDHeader P1Safe ModeLogic LevelsGPIO Configuration at Reset1-Wire DriverHeader P5Reset
/proc/meminfoMemTotalMemFreeBuffersCachedSwapCachedActiveInactiveActive(anon)Inactive(anon)Active(file)Inactive(file)UnevictableMlockedSwapTotalSwapFreeDirtyWritebackAnonPagesMappedShmemSlabSReclaimableSUnreclaimKernelStackPageTablesNFS_UnstableBounceWritebackTmpCommitLimitCommitted_ASVmallocTotalVmallocUsedVmallocChunkPhysical MemoryMemory MappingAddressLengthProtectionFlagsFile DescriptorOffsetReturn ValueVolatileVirtual MemoryFinal Thoughts on SDRAM
IdentificationOverclockingExecutionThreadspthread Headerspthread Error Handlingpthread_create(3)pthread_attr_tpthread_join(3)pthread_detach(3)pthread_self(3)pthread_kill(3)Mutexespthread_mutex_create(3)pthread_mutex_destroy(3)pthread_mutex_lock(3)pthread_mutex_unlock(3)Condition Variablespthread_cond_init(3)pthread_cond_destroy(3)pthread_cond_wait(3)pthread_cond_signal(3)pthread_cond_broadcast(3)
PowerPowered HubsUSB API SupportlibusbInclude Files
Wired Ethernet/etc/network/interfacesChanging to Static IPTest Static IP AddressUSB Adapters/etc/hosts FileWireless EthernetConfiguration
SD Card MediaSD Card InterfaceSD Card BasicsRaspbian Block SizeDisk CacheCapacities and PerformanceTransfer ModesSPI Bus Mode1-bit SD Mode4-bit SD ModeWear Leveling
RS-232 ConverterDTE or DCERS-232Start BitData BitsParity BitStop Bit(s)Baud RateBreakFlow ControlRaspberry Pi UARTsARM PL011 UARTRTS/CTS AccessPL011 UART FeaturesExclusive Serial Line UseProcedureVerificationSerial APIHeader Filesopen(2)struct termiostcgetattr(3)tcsetattr(3)tcsendbreak(3)tcdrain(3)tcflush(3)tcflow(3)cfmakeraw(3)cfgetispeed(3)cfgetospeed(3)cfsetispeed(3)cfsetospeed(3)cfsetspeed(3)read(2)write(2)readv(2) and writev(2)Error EINTR
Pins and DesignationsConfiguration After ResetPull-up ResistorsConfiguring Pull-up ResistorsTesting Pull-up StateLogic LevelsDrive StrengthInput PinsOutput PinsDriving Bi-color LEDsTesting Drive StrengthGPIO Current BudgetConfigurationAlternate Function SelectOutput PinsInput PinsAlternate FunctionSysfs GPIO AccessexportunexportgpioXChip LevelGPIO TesterGPIO Input TestFloating PotentialsReading EventsTest RunDirect Register Accessgpio_init()gpio_config()gpio_write()gpio_read()gpio_io.cGPIO Transistor DriverDriver DesignSubstitutionInductive LoadsDriver SummaryUtility gpioDisplaying GPIO SettingsReading GPIOWriting GPIOModify Drive Levels
1-Wire Line and PowerLine DrivingMaster and SlaveProtocolResetData I/OSlave SupportReading TemperatureBus MasterSlave DevicesReading the Temperature1-Wire GPIO Pin
I2C OverviewSDA and SCLMultimaster and ArbitrationBus SignalingData BitsMessage FormatsWhich I2C Bus?I2C Bus SpeedToolsI2C APIKernel Module SupportHeader Filesopen(2)ioctl(2,I2C_FUNC)ioctl(2,I2C_RDWR)
SPI BasicsSPI ModeSignalingSlave SelectionDriver SupportSPI APIOpen DeviceSPI Mode MacrosBits per WordClock RateData I/OCloseWriteReadSPI Testing
Ohm’s LawPowerUnits

Content preview from Raspberry Pi Hardware Reference

CHAPTER 6

USB

The USB port has become ubiquitous in the digital world, allowing the use of a large choice of peripherals. The Model B Raspberry Pi supports two USB 2 ports, and the Model A just one.

This chapter briefly examines some power considerations associated with USB support and powered hubs. The remainder of this chapter examines the device driver interface available to the Raspbian Linux developer. Figure 6-1 serves as a chapter reference schematic of the Raspberry USB interface.