Mike at 14:18, 23 December 2009

2009-12-23T14:18:31Z

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The WinCE demo image includes the SPI driver that allows direct access to the SPI controllers.
<br>
The SPI driver is a stream driver that can be accessed using the "SPI" prefix.
== SPI driver API ==
{{API | Signature = HANDLE SPIOpen(LPCTSTR pSpiName) |
Description = Opens an instance of the SPI Driver. Returns a handle that should be used to access the driver |
Return = NULL indicates failure, otherwise a driver handle is returned. |
Param1 = *pSpiName - A string that indicates which SPI controller is accessed by this driver instance. Allowed names are:
<pre>
#define SPI1_DEVICE_NAME L"SPI1:" //SPI1
#define SPI2_DEVICE_NAME L"SPI2:" //SPI2
#define SPI3_DEVICE_NAME L"SPI3:" //SPI3
#define SPI4_DEVICE_NAME L"SPI4:" //SPI4
</pre> |
Param2 = |
Param3 = |
Param4 = |
Remarks = }}

{{API | Signature = void SPIClose(HANDLE hContext) |
Description = This function closes the handle to the driver |
Return = None |
Param1 = *hContext - Handle to an open driver instance|
Param2 = |
Param3 = |
Param4 = |
Remarks = }}

{{API | Signature = BOOL SPIConfigure(HANDLE hContext, DWORD address, DWORD config) |
Description = This function is used to configure the SPI channel|
Return = None |
Param1 = *hContext - Handle to an open driver instance|
Param2 = *address - SPI slave address|
Param3 = *config - The needed value for MCSPI_CHxCONF, you can use the following macros:
<pre>
/* CHCONF Register Bit values */
//Data are latched on odd-numbered edges of spim_clk.
#define MCSPI_PHA_ODD_EDGES (0 << 0)
//Data are latched on even-numbered edges of spim_clk.
#define MCSPI_PHA_EVEN_EDGES (1 << 0)

//spim_clk is held high during the active state
#define MCSPI_POL_ACTIVEHIGH (0 << 1)
//spim_clk is held low during the active state
#define MCSPI_POL_ACTIVELOW (1 << 1)

//Frequency divider for spim_clk (for master device only)
#define MCSPI_CHCONF_CLKD(x) ((x & 0x0F) << 2)

//SPIM_CSX is held high during the active state
#define MCSPI_CSPOLARITY_ACTIVEHIGH (0 << 6)
//SPIM_CSX is held low during the active state
#define MCSPI_CSPOLARITY_ACTIVELOW (1 << 6)

//SPI word length (4 <= x && 32 >= x)
#define MCSPI_CHCONF_WL(x) (((x-1) & 0x1F) << 7)
#define MCSPI_CHCONF_GET_WL(x) (((x >> 7) & 0x1F) +1)

//Transmit/receive modes
#define MCSPI_CHCONF_TRM_TXRX (0 << 12) //Transmit and receive mode
#define MCSPI_CHCONF_TRM_RXONLY (1 << 12) //Receive-only mode
#define MCSPI_CHCONF_TRM_TXONLY (2 << 12) //Transmit-only mode

/*
When enabled, the DMA write request line is asserted when the channel is
enabled and the MCSPI_TXx register of the channel is empty.
*/
#define MCSPI_CHCONF_DMAW_ENABLE (1 << 14) //enabled
#define MCSPI_CHCONF_DMAW_DISABLE (0 << 14) //disabled

/**
The DMA Read request line is asserted when the channel is
enabled and a new data is available in the receive register of the
channel.
*/
#define MCSPI_CHCONF_DMAR_ENABLE (1 << 15) //enabled
#define MCSPI_CHCONF_DMAR_DISABLE (0 << 15) //disabled

//No transmission on data Line 0 (spim_somi)
#define MCSPI_CHCONF_DPE0 (1 << 16)
//No transmission on data Line 1 (spim_simo)
#define MCSPI_CHCONF_DPE1 (1 << 17)
//Input select - Data Line 1 (spim_simo) selected for reception
#define MCSPI_CHCONF_IS (1 << 18)
//Turbo mode - Turbo is activated to maximize the throughput for multi-SPI word transfers.
#define MCSPI_CHCONF_TURBO (1 << 19)

/**
Manual SPIM_CSX assertion to keep SPIM_CSX for the channel
active between SPI words (single channel master mode only).
*/
#define MCSPI_CHCONF_FORCE (1 << 20)

/**
Channel 0 only and slave mode only: SPI slave select signal detection.
0x0: Detection enabled only on spim_cs0
0x1: Detection enabled only on spim_cs1
0x2: Detection enabled only on spim_cs2
0x3: Detection enabled only on spim_cs3
*/
#define MCSPI_CHCONF_SPIENSLV(CSn) ((CSn & 0x03) << 21)

// Defines number of interface clock cycles between CS toggling and first/last edge of SPI clock
#define MCSPI_CHCONF_TCS_0P5_CLOCKS (0 << 25)
#define MCSPI_CHCONF_TCS_1P5_CLOCKS (1 << 25)
#define MCSPI_CHCONF_TCS_2P5_CLOCKS (2 << 25)
#define MCSPI_CHCONF_TCS_3P5_CLOCKS (3 << 25)
</pre>
|
Param4 = |
Remarks = You can read more about the MCSPI_CHCONF register in the OMAP35x Technical reference manual.}}

{{API | Signature = DWORD SPIRead(HANDLE hContext, DWORD size, VOID *pBuffer) |
Description = This function reads data from the device identified by the open context. |
Return = The number of bytes read.|
Param1 = *hContext - Handle to an open driver instance.|
Param2 = *size - Number of bytes to be read from the device.|
Param3 = *pBuffer - Pointer to the buffer that receives the data read from the device.|
Param4 = |
Remarks = This operation is only allowed for MCSPI_CHCONF_TRM_RXONLY channels as configured in [[#BOOL_SPIConfigure.28HANDLE_hContext.2C_DWORD_address.2C_DWORD_config.29 | SPIConfigure]].}}

{{API | Signature = DWORD SPIWrite(HANDLE hContext, DWORD size, VOID *pBuffer) |
Description = This function writes data to the device identified by the open context. |
Return = The number of bytes written.|
Param1 = *hContext - Handle to an open driver instance.|
Param2 = *size - Number of bytes to write to the device.|
Param3 = *pBuffer - Pointer to the buffer containing the data to write to the device.|
Param4 = |
Remarks = This operation is only allowed for MCSPI_CHCONF_TRM_TXONLY channels as configured in [[#BOOL_SPIConfigure.28HANDLE_hContext.2C_DWORD_address.2C_DWORD_config.29 | SPIConfigure]].}}

{{API | Signature = DWORD SPIWriteRead(HANDLE hContext, DWORD size, VOID *pOutBuffer, VOID *pInBuffer)|
Description = This function writes and reads data to/from the device identified by the open context. |
Return = The number of bytes read.|
Param1 = *hContext - Handle to an open driver instance.|
Param2 = *size - Number of bytes to write and read from/to the device.|
Param3 = *pOutBuffer - Pointer to the buffer that receives the data read from the device.|
Param4 = *pInBuffer - Pointer to the buffer containing the data to write to the device.|
Remarks = *Both buffers must be the same length.
:*This operation is only allowed for MCSPI_CHCONF_TRM_TXRX channels as configured in [[#BOOL_SPIConfigure.28HANDLE_hContext.2C_DWORD_address.2C_DWORD_config.29 | SPIConfigure]].}}

== SPI Sample Application ==

SPI Driver API for CM-T3530 - Revision history

Mike at 14:18, 23 December 2009