Difference between revisions of "Unit SPI"

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! '''Return'''
 
! '''Return'''
 
| ERROR_SUCCESS if completed or another error code on failure
 
| ERROR_SUCCESS if completed or another error code on failure
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</div></div>
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<div class="toccolours mw-collapsible mw-collapsed" style="border: 1; font-family: arial; padding-top: 0px; padding-bottom: 15px;">
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<pre style="border: 0; padding-bottom:0px;">function SysSPIWrite(ChipSelect:Word; Source:Pointer; Size:LongWord; var Count:LongWord):LongWord;</pre>
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<div style="font-size: 14px; padding-left: 12px;">'''Description:''' Write data to the default SPI device</div>
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{| class="wikitable" style="font-size: 14px; background: white;"
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|-
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! '''ChipSet'''
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| The chip select for the slave to write to (eg SPI_CS_0)
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|-
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! '''Source'''
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| Pointer to a buffer of data to transmit
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|-
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! '''Size'''
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| The size of the buffer
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|-
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! '''Count'''
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| The number of bytes written on return
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|-
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! '''Return'''
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| ERROR_SUCCESS if completed or another error code on failure
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|-
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! '''Note'''
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| Because SPI writes and then reads for each byte, received data will be discarded for each by written
 
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Revision as of 05:06, 2 September 2016

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Description

SPI (Serial Peripheral Interface) is a synchronous serial bus for communication with peripheral components.

The SPI protocol is not defined by any actual standard but some psuedo standards exist with all of the available devices. SPI is a master-slave protocol where the master asserts the chip selectline (CS) to select the slave device before sending data one byte at a time. For every byte written to the bus by the master the selected slave returns a byte as well so for every write there is an equivalent read. SPI can also operate in either 4 wire (standard) or 3 wire(bidirectional) modes.

Due to the lack of formal standards and the range of devices that exist various options are provided to allow setting clock phase and polarity as well chip select polarity.

For the purpose of this interface a device is the SPI controller attached to the local system and may be either a master or a slave. Since the protocol does not include any form of enumeration or identification the interface does not attempt to represent the devices connected to the bus, any driver written to communicate with a connected SPI device should know (or allow configuration of) the chip select for the for the device and the specific message format required for that device.

Constants

To be documented

Type definitions

To be documented

Public variables

To be documented

Function declarations


Initialization functions

[Expand] 
procedure SPIInit;
Description: Initialize the SPI unit and SPI device table


SPI functions

[Expand] 
function SPIDeviceStart(SPI:PSPIDevice; Mode,ClockRate,ClockPhase,ClockPolarity:LongWord):LongWord;
Description: Start the specified SPI device ready for writing and reading


[Expand] 
function SPIDeviceStop(SPI:PSPIDevice):LongWord;
Description: Stop the specified SPI device and terminate writing and reading


[Expand] 
function SPIDeviceWrite(SPI:PSPIDevice; ChipSelect:Word; Source:Pointer; Size,Flags:LongWord; var Count:LongWord):LongWord;
Description: Write data to the specified SPI device


[Expand] 
function SPIDeviceSetMode(SPI:PSPIDevice; Mode:LongWord):LongWord;
Description: Set the device mode for the specified SPI device


[Expand] 
function SPIDeviceSetClockRate(SPI:PSPIDevice; ClockRate:LongWord):LongWord;
Description: Set the clock rate for the specified SPI device


[Expand] 
function SPIDeviceSetClockPhase(SPI:PSPIDevice; ClockPhase:LongWord):LongWord;
Description: Set the clock phase for the specified SPI device


[Expand] 
function SPIDeviceSetClockPolarity(SPI:PSPIDevice; ClockPolarity:LongWord):LongWord;
Description: Set the clock polarity for the specified SPI device


[Expand] 
function SPIDeviceSetSelectPolarity(SPI:PSPIDevice; ChipSelect:Word; SelectPolarity:LongWord):LongWord;
Description: Set the chip select polarity for the specified SPI device


[Expand] 
function SPIDeviceCreate:PSPIDevice;
Description: Create a new SPI entry


[Expand] 
function SPIDeviceCreateEx(Size:LongWord):PSPIDevice;
Description: Create a new SPI entry


[Expand] 
function SPIDeviceDestroy(SPI:PSPIDevice):LongWord;
Description: Destroy an existing SPI entry


[Expand] 
function SPIDeviceRegister(SPI:PSPIDevice):LongWord;
Description: Register a new SPI in the SPI table


[Expand] 
function SPIDeviceFind(SPIId:LongWord):PSPIDevice;
Description: To be documented


[Expand] 
function SPIDeviceFindByName(const Name:String):PSPIDevice; inline;
Description: To be documented


[Expand] 
function SPIDeviceFindByDescription(const Description:String):PSPIDevice; inline;
Description: To be documented


[Expand] 
function SPIDeviceEnumerate(Callback:TSPIEnumerate; Data:Pointer):LongWord;
Description: To be documented


[Expand] 
function SPIDeviceNotification(SPI:PSPIDevice; Callback:TSPINotification; Data:Pointer; Notification,Flags:LongWord):LongWord;
Description: To be documented


RTL SPI functions

[Expand] 
function SysSPIAvailable:Boolean;
Description: Check if an SPI device is available


[Expand] 
function SysSPIStart(Mode,ClockRate,ClockPhase,ClockPolarity:LongWord):LongWord;
Description: Start the default SPI device ready for writing and reading


[Expand] 
function SysSPIStop:LongWord;
Description: Stop the default SPI device and terminate writing and reading


[Expand] 
function SysSPIWrite(ChipSelect:Word; Source:Pointer; Size:LongWord; var Count:LongWord):LongWord;
Description: Write data to the default SPI device


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