Difference between revisions of "Unit BCM2708"

Revision as of 04:32, 29 December 2016

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Description

Ultibo BCM2708 interface unit

This unit provides the BCM2708 specific implementations of the following devices:

• SPI0
• I2C0
• I2C1
• SPI1
• SPI2
• I2C Slave
• SPI Slave
• DMA
• PWM0
• PWM1
• PCM
• GPIO
• UART0
• UART1
• SDHCI (eMMC)

• Clock
• ARM Timer
• Random
• Mailbox
• Watchdog
• Framebuffer

• MIPI CSI-2 (Camera Serial Interface)
• DSI (Display Serial Interface)

BCM2708 SPI0 Device

The BCM2708 has a single master mode SPI controller that supports 3 wire, 2 wire and LoSSI modes of operation. It also has 2 auxiliary SPI masters which do not support DMA mode (see SPI1/2 below).

The main SPI0 controller supports polled, interrupt and DMA modes and includes 3 chip selects although only CS0 and 1 are available on the 26 or 40 pin header.

By default SPI0 can appear on GPIO pins 7 to 11 (CS1, CS0, MISO, MOSI, SCLK) using alternate function 0 or on GPIO pins 35 to 39 (CS1, CS0, MISO, MOSI, SCLK) using alternate function 0, only pins 7 to 11 are available on the header.

BCM2708 I2C0/1 Device

The BCM2708 has 3 Broadcom Serial Controller (BSC) devices which are fast mode (400Kz) masters numbered BSC0, BSC1 and BSC2.

Device BSC2 is dedicated to the HDMI interface and is not availale for use by the ARM processor. All BSC devices contain a 16 byte FIFO, support 7 bit and 10 bit addressing and have software configurable clock timing.

By default BSC0 can appear on GPIO pins 0 and 1 (Alternate function 0), 28 and 29 (Alternate function 0) or 44 and 45 (Alternate function 1). Unfortunately on all except the Revision 1 models none of these pins are available on the 26 or 40 pin header.

Note: On the Raspberry Pi A+/B+/Zero/2B/3B the ID EEPROM pins on the 40 pin header are actually connected to GPIO 0 and 1 (BSC0)

Device BSC1 can appear on GPIO pins 2 and 3 (Alternate function 0) or 44 and 45 (Alternate function 2) but only pins 2 and 3 are exposed on the 26 or 40 pin header.

BCM2708 SPI1/2 Device

The BCM2708 has 2 additional SPI universal masters available as part of the AUX device which support interrupt mode but not DMA and therefore only allow limited bandwidth transfers due to the CPU overhead required to sustain high data rates.

Both devices support 3 chip selects, by default SPI1 is available on GPIO pins 16 to 21 (CS2, CS1, CS0, MISO, MOSI, SCLK) using alternate function 4 and SPI2 is available on GPIO pins 40 to 45 (MISO, MOSI, SCLK, CS0, CS1, CS2) using alternate function 4. Only pins 16 to 21 are available on the header and only on the 40 pin header of the Raspberry Pi A+/B+/Zero/2B/3B.

BCM2708 DMA Device

The DMA controller has 16 channels in total although not all are available for software to use as some are already used by the GPU.

The firmware will pass the value dma.dmachans on the command line which will indicate which channels are available for our use.

Channels 0 to 6 are normal channels which support 2D stride and transfers up to 1GB per control block

Channels 7 to 14 are Lite channels which do not support stride and only allow transfers up to 64KB per control block

Channel 15 is not mentioned in most documentation and is shown as not available in the mask passed in dma.dmachans

Channel 0 and 15 are Bulk channels which have an additional FIFO for faster transfers (8 beat burst per read)

BCM2708 PWM0/1 Device

The BCM2708 has a single PWM controller with 2 independent output bit streams with multiple algorithms for generating the output pulse. The PWM controller supports either a single data register (independent per channel) or a 16 x 32 FIFO which also supports DMA mode transmission.

On the Raspberry Pi PWM0 and PWM1 are also connected via GPIO pins 40 and 45 (40 and 41 on the Raspberry Pi 3B) to the audio circuit and allow playback of digital audio signals via the 3 or 4 pole line jack (depending on model).

PWM0 is available on GPIO pins 12 (function 0), 18 (function 5), 40 (function 0) and 52 (function 1).

PWM1 is available on GPIO pins 13 (function 0), 19 (function 5), 41, 45 (function 0) and 53 (function 1).

On the Raspberry Pi A and B only pin 18 is exposed on the 26 pin header.

On the Raspberry Pi A+/B+/Zero/2B/3B pins 12, 18 and 19 are exposed on the 40 pin header.

BCM2708 GPIO Device

The GPIO has 54 pins available each with multiple alternate functions. All pins can be configured as input or output and all can have pull up or down applied.

Not all pins are exposed on the 26 or 40 pin header of the Raspberry Pi, for details of which pins are available see:

Raspberry Pi A and B - https://www.raspberrypi.org/documentation/usage/gpio/README.md

Raspberry Pi A+/B+/2B/3B/Zero - https://www.raspberrypi.org/documentation/usage/gpio-plus-and-raspi2/README.md

Some of the 54 pins are used for peripheral communication (such as the SD card) and are not available for general use,take care when changing function selects on pins to avoid disabling certain system peripherals.

Event detection can be enabled for both high and low levels as well as rising and falling edges, there is also an asynchronous rising or falling edge detection which can detect edges of very short duration.

BCM2708 UART0 Device

The UART0 device is an ARM PL011 UART which supports programmable baud rates, start, stop and parity bits and hardware flow control and many others. The UART0 is similar to the industry standard 16C650 but with a number of differences, the PL011 has a some optional features such as IrDA, Serial InfraRed and DMA which are not supported by the Broadcom implementation. In the standard configuration the UART0 TX and RX lines are connected to GPIO pins 14 and 15 respectively (Alternate function 0) but they can be remapped via GPIO function selects to a number of other locations. On the Raspberry Pi (all models) none of these alternate pin mappings are exposed via the 26 or 40 pin header and therefore cannot be used easily. This means that UART0 and UART1 cannot be used at the same time.

On the Raspberry Pi 3B the UART0 can be mapped to GPIO pins 32 and 33 (Alternate function 3) to communicate with the built in Bluetooth module.

BCM2708 UART1 Device

The UART1 device is a Broadcom implementation that is part of the AUX device which also includes the SPI1 and SPI2 devices. This device is termed a Mini UART and has a smaller feature set than the PL011 UART but still supports a fairly standard communication protocol with programmable baud rate and hardware flow control.

The Mini UART is similar to the standard 16550 device but is missing some of the features, the device also has no DMA support so high speed transfers will produce a higher CPU load. In the standard configuration the UART1 TX and RX lines are connected to GPIO pins 14 and 15 respectively (Alternate function 5) but they can be remapped via GPIO function selects to a number of other locations. On the Raspberry Pi (all models) none of these alternate pin mappings are exposed via the 26 or 40 pin header and therefore cannot be used easily. This means that UART0 and UART1 cannot be used at the same time.

On the Raspberry Pi 3B the UART1 can be mapped to GPIO pins 32 and 33 (Alternate function 5) to communicate with the built in Bluetooth module.

BCM2708 SDHCI Device

The SDHCI controller on the BCM2708 is an Arasan SD Host controller.

The Card Detect pin is connected to GPIO pin 47 (on the RPi Model A/B)(Not connected on the RPi Model A+/B+)

The Write Protect pin is not connected on any RPi model.

BCM2708 Clock (System Timer) Device

The clock device in the BCM2708 is based on the System Timer which is a 64 bit free running counter that runs at 1MHz regardless of core or CPU clock speeds. The System Timer cannot be stopped and the counter cannot be set or reset.

The System Timer includes 4 compare registers which can each generate an interrupt when the compare value is matched, however 2 of the 4 are consumed by the GPU and on the Raspberry Pi A/B/A+/B+/Zero the other 2 are used for the scheduler and clock interrupts in Ultibo.

This device simply exposes the free running counter as a clock value and does not provide access to the timer compare functionality or to interrupt based events, for those see the timer devices below.

BCM2708 Clock (ARM Timer) Device

This device represents that free running counter from the ARM Timer device (below) as a clock device. The free running counter does not appear in the original SP804 timer. The counter is 32 bits wide and has its own divider that is 8 bits wide meaning that it can be set to clock rates of between 975KHz and 250MHz (or 1.5MHz to 400MHz on the Raspberry Pi 3B).

The counter does not generate an interrupt and cannot be set or reset but it can be stopped and started.

BCM2708 ARM Timer Device

The ARM Timer device in the BCM2708 is based on the ARM SP804 timer with some modifications and additions. In the Raspberry Pi it is connected to the core clock which by default is 250MHz but was increased to 400MHz on the Raspberry Pi 3B.

The divider is 10 bits wide which means that the ARM Timer can be set to clock rates of between 250KHz and 250MHz (or 400KHz to 400MHz on the Raspberry Pi 3B). Both the counter and the load/reload value are 32 bits wide by default giving a wide range of tick intervals.

The ARM Timer features a free running counter which is not enabled or used by this driver and a down counter which operates in wrapping mode so that each time it reaches 0 it triggers an interrupt and reloads the value from a load or reload register to begin counting again.

Constants

Type definitions

To be documented

Public variables

To be documented

Function declarations

Initialization functions

procedure BCM2708Init;

BCM2708 SPI0 functions

function BCM2708SPI0Start(SPI:PSPIDevice;Mode,ClockRate,ClockPhase,ClockPolarity:LongWord):LongWord;

function BCM2708SPI0Stop(SPI:PSPIDevice):LongWord;

function BCM2708SPI0WriteRead(SPI:PSPIDevice; ChipSelect:Word; Source,Dest:Pointer; Size,Flags: LongWord; var Count:LongWord):LongWord;

function BCM2708SPI0SetMode(SPI:PSPIDevice; Mode:LongWord):LongWord;

function BCM2708SPI0SetClockRate(SPI:PSPIDevice; ChipSelect:Word; ClockRate:LongWord):LongWord;

function BCM2708SPI0SetClockPhase(SPI:PSPIDevice; ClockPhase:LongWord):LongWord;

function BCM2708SPI0SetClockPolarity(SPI:PSPIDevice; ClockPolarity:LongWord):LongWord;

function BCM2708SPI0SetSelectPolarity(SPI:PSPIDevice; ChipSelect:Word; SelectPolarity:LongWord):LongWord;

procedure BCM2708SPI0ReadFIFO(SPI:PBCM2708SPI0Device);

procedure BCM2708SPI0WriteFIFO(SPI:PBCM2708SPI0Device);

procedure BCM2708SPI0InterruptHandler(SPI:PBCM2708SPI0Device);

procedure BCM2708SPI0DMARequestCompleted(Request:PDMARequest);

BCM2708 BSCI2C (I2C0/1) functions

function BCM2708BSCI2CStart(I2C:PI2CDevice; Rate:LongWord):LongWord;

function BCM2708BSCI2CStop(I2C:PI2CDevice):LongWord;

function BCM2708BSCI2CRead(I2C:PI2CDevice; Address:Word; Buffer:Pointer; Size:LongWord; var Count:LongWord):LongWord;

function BCM2708BSCI2CWrite(I2C:PI2CDevice; Address:Word; Buffer:Pointer; Size:LongWord; var Count:LongWord):LongWord;

function BCM2708BSCI2CWriteRead(I2C:PI2CDevice; Address:Word; Initial:Pointer; Len:LongWord; Data:Pointer; Size:LongWord; var Count:LongWord):LongWord;

function BCM2708BSCI2CWriteWrite(I2C:PI2CDevice; Address:Word; Initial:Pointer; Len:LongWord; Data:Pointer; Size:LongWord; var Count:LongWord):LongWord;

function BCM2708BSCI2CSetRate(I2C:PI2CDevice; Rate:LongWord):LongWord;

function BCM2708BSCI2CSetAddress(I2C:PI2CDevice; Address:Word):LongWord;

procedure BCM2708BSCI2CFillFIFO(I2C:PBCM2708BSCI2CDevice);

procedure BCM2708BSCI2CDrainFIFO(I2C:PBCM2708BSCI2CDevice);

procedure BCM2708BSCI2CInterruptHandler(IRQData:PBCM2708BSCI2CIRQData);

BCM2708 DMA functions

function BCM2708DMAHostStart(DMA:PDMAHost):LongWord;

function BCM2708DMAHostStop(DMA:PDMAHost):LongWord;

function BCM2708DMAHostSubmit(DMA:PDMAHost; Request:PDMARequest):LongWord;

function BCM2708DMAHostCancel(DMA:PDMAHost; Request:PDMARequest):LongWord;

procedure BCM2708DMAInterruptHandler(Channel:PBCM2708DMAChannel);

procedure BCM2708DMASharedInterruptHandler(DMA:PBCM2708DMAHost);

procedure BCM2708DMARequestComplete(Channel:PBCM2708DMAChannel);

function BCM2708DMAPeripheralToDREQ(Peripheral:LongWord):LongWord;

procedure BCM2708DMADataToControlBlock(Request:PDMARequest; Data:PDMAData; Block:PBCM2835DMAControlBlock; Bulk,Lite:Boolean);

BCM2708 PWM0/1 functions

function BCM2708PWMStart(PWM:PPWMDevice):LongWord;

function BCM2708PWMStop(PWM:PPWMDevice):LongWord;

function BCM2708PWMWrite(PWM:PPWMDevice; Value:LongWord):LongWord;

function BCM2708PWMSetGPIO(PWM:PPWMDevice; GPIO:LongWord):LongWord;

function BCM2708PWMResetGPIO(PWM:PPWMDevice; GPIO:LongWord):LongWord;

function BCM2708PWMSetMode(PWM:PPWMDevice; Mode:LongWord):LongWord;

function BCM2708PWMSetRange(PWM:PPWMDevice; Range:LongWord):LongWord;

function BCM2708PWMSetFrequency(PWM:PPWMDevice; Frequency:LongWord):LongWord;

function BCM2708PWMSetPolarity(PWM:PPWMDevice; Polarity:LongWord):LongWord;

function BCM2708PWMConfigure(PWM:PPWMDevice; DutyNS,PeriodNS:LongWord):LongWord;

function BCM2708PWMClockStart(PWM:PPWMDevice; Frequency:LongWord):LongWord;

function BCM2708PWMClockStop(PWM:PPWMDevice):LongWord;

function BCM2708PWMClockEnabled(PWM:PPWMDevice):Boolean;

BCM2708 GPIO functions

function BCM2708GPIOStart(GPIO:PGPIODevice):LongWord;

function BCM2708GPIOStop(GPIO:PGPIODevice):LongWord;

function BCM2708GPIORead(GPIO:PGPIODevice;Reg:LongWord):LongWord;

procedure BCM2708GPIOWrite(GPIO:PGPIODevice; Reg,Value:LongWord);

function BCM2708GPIOInputGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;

function BCM2708GPIOInputWait(GPIO:PGPIODevice; Pin,Trigger,Timeout:LongWord):LongWord;

function BCM2708GPIOInputEvent(GPIO:PGPIODevice; Pin,Trigger,Flags,Timeout:LongWord; Callback:TGPIOCallback; Data:Pointer):LongWord;

function BCM2708GPIOInputCancel(GPIO:PGPIODevice; Pin:LongWord):LongWord;

function BCM2708GPIOOutputSet(GPIO:PGPIODevice; Pin,Level:LongWord):LongWord;

function BCM2708GPIOPullSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;

function BCM2708GPIOFunctionGet(GPIO:PGPIODevice; Pin:LongWord):LongWord;

function BCM2708GPIOFunctionSelect(GPIO:PGPIODevice; Pin,Mode:LongWord):LongWord;

procedure BCM2708GPIOInterruptHandler(Bank:PBCM2708GPIOBank);

procedure BCM2708GPIOEventTrigger(Pin:PGPIOPin);

procedure BCM2708GPIOEventTimeout(Event:PGPIOEvent);

BCM2708 UART0 functions

function BCM2708UART0Open(UART:PUARTDevice; BaudRate,DataBits,StopBits,Parity,FlowControl:LongWord):LongWord;

function BCM2708UART0Close(UART:PUARTDevice):LongWord;

function BCM2708UART0Read(UART:PUARTDevice; Buffer:Pointer; Size,Flags:LongWord; var Count:LongWord):LongWord;

function BCM2708UART0Write(UART:PUARTDevice; Buffer:Pointer; Size,Flags:LongWord; var Count:LongWord):LongWord;

function BCM2708UART0Status(UART:PUARTDevice):LongWord;

procedure BCM2708UART0InterruptHandler(UART:PUARTDevice);

procedure BCM2708UART0Receive(UART:PUARTDevice);

procedure BCM2708UART0Transmit(UART:PUARTDevice);

BCM2708 SDHCI functions

function BCM2708SDHCIHostStart(SDHCI:PSDHCIHost):LongWord;

function BCM2708SDHCIHostStop(SDHCI:PSDHCIHost):LongWord;

function BCM2708SDHCIHostReadByte(SDHCI:PSDHCIHost; Reg:LongWord):Byte;

function BCM2708SDHCIHostReadWord(SDHCI:PSDHCIHost; Reg:LongWord):Word;

function BCM2708SDHCIHostReadLong(SDHCI:PSDHCIHost; Reg:LongWord):LongWord;

procedure BCM2708SDHCIHostWriteByte(SDHCI:PSDHCIHost; Reg:LongWord; Value:Byte);

procedure BCM2708SDHCIHostWriteWord(SDHCI:PSDHCIHost; Reg:LongWord; Value:Word);

procedure BCM2708SDHCIHostWriteLong(SDHCI:PSDHCIHost; Reg:LongWord; Value:LongWord);

procedure BCM2708SDHCIInterruptHandler(SDHCI:PSDHCIHost);

function BCM2708SDHCISetupInterrupts(SDHCI:PSDHCIHost):LongWord;

function BCM2708MMCDeviceGetCardDetect(MMC:PMMCDevice):LongWord;

BCM2708 system clock functions

function BCM2708SystemClockRead(Clock:PClockDevice):LongWord;

function BCM2708SystemClockRead64(Clock:PClockDevice):Int64;

BCM2708 ARM block functions

function BCM2708ARMClockStart(Clock:PClockDevice):LongWord;

function BCM2708ARMClockStop(Clock:PClockDevice):LongWord;

function BCM2708ARMClockRead(Clock:PClockDevice):LongWord;

function BCM2708ARMClockRead64(Clock:PClockDevice):Int64;

function BCM2708ARMClockSetRate(Clock:PClockDevice; Rate:LongWord):LongWord;

BCM2708 ARM timer functions

function BCM2708ARMTimerStart(Timer:PTimerDevice):LongWord;

function BCM2708ARMTimerStop(Timer:PTimerDevice):LongWord;

function BCM2708ARMTimerRead64(Timer:PTimerDevice):Int64;

function BCM2708ARMTimerWait(Timer:PTimerDevice):LongWord;

function BCM2708ARMTimerEvent(Timer:PTimerDevice; Flags:LongWord; Callback:TTimerCallback; Data:Pointer):LongWord;

function BCM2708ARMTimerCancel(Timer:PTimerDevice):LongWord;

function BCM2708ARMTimerSetRate(Timer:PTimerDevice; Rate:LongWord):LongWord;

function BCM2708ARMTimerSetInterval(Timer:PTimerDevice; Interval:LongWord):LongWord;

procedure BCM2708ARMTimerInterruptHandler(Timer:PTimerDevice);

procedure BCM2708ARMTimerEventTrigger(Timer:PTimerDevice);

BCM2708 random functions

function BCM2708RandomStart(Random:PRandomDevice):LongWord;

function BCM2708RandomStop(Random:PRandomDevice):LongWord;

function BCM2708RandomReadLongWord(Random:PRandomDevice):LongWord;

BCM2708 watchdog functions

function BCM2708WatchdogStart(Watchdog:PWatchdogDevice):LongWord;

function BCM2708WatchdogStop(Watchdog:PWatchdogDevice):LongWord;

function BCM2708WatchdogRefresh(Watchdog:PWatchdogDevice):LongWord;

function BCM2708WatchdogGetRemain(Watchdog:PWatchdogDevice):LongWord;

BCM2708 framebuffer functions

function BCM2708FramebufferAllocate(Framebuffer:PFramebufferDevice; Properties:PFramebufferProperties):LongWord;

function BCM2708FramebufferRelease(Framebuffer:PFramebufferDevice):LongWord;

function BCM2708FramebufferBlank(Framebuffer:PFramebufferDevice; Blank:Boolean):LongWord;

function BCM2708FramebufferCommit(Framebuffer:PFramebufferDevice; Address,Size,Flags:LongWord):LongWord;

function BCM2708FramebufferWaitSync(Framebuffer:PFramebufferDevice):LongWord;

function BCM2708FramebufferSetOffset(Framebuffer:PFramebufferDevice; X,Y:LongWord; Pan:Boolean):LongWord;

function BCM2708FramebufferGetPalette(Framebuffer:PFramebufferDevice; Palette:PFramebufferPalette):LongWord;

function BCM2708FramebufferSetPalette(Framebuffer:PFramebufferDevice; Palette:PFramebufferPalette):LongWord;

function BCM2708FramebufferSetBacklight(Framebuffer:PFramebufferDevice; Brightness:LongWord):LongWord;

function BCM2708FramebufferSetProperties(Framebuffer:PFramebufferDevice; Properties:PFramebufferProperties):LongWord;

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