Kostyas at 16:18, 15 March 2010

2010-03-15T16:18:06Z

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= Introduction =
The SPI sample application demonstrates the SPI communication between EM-X270 and Maxim Semiconductor DS1722 thermometer. The DS1722 manual is available at: [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2766/t/al DS1722 manual].

This sample is located in the EM-X270 run-time image package at {{Filename|\x270-em-wince6-img\Demo Applications\SPI_Thermometer}} folder.

= SPI Sample =
controller.
== Connecting the device to EM-X270 ==
* The SPI device can be connected to the SSP1 port available on the connector P6 on EB-X270. The following table describes the SSP pins:
{|cellpadding="3" border="1" style="border: 1px solid rgb(85, 85, 85); border-collapse: collapse;"
| '''EB-X270 P6 Pin Number''' || '''DS1722 Pin Number'''
|-
|1 (SSP1_TXD) || 6 (SDI)
|-
|2 (SSP1_RXD) || 5 (SDO)
|-
|3 (SSP1_CLK) || 3 (SCLK)
|}
* Connect EM-X270 GPIO 108 (GPIO used as SPI chip select) to pin 2 (CE) of DS1722.
* Connect pin 6 (SERMODE) of DS1722 to VDD.
* Connect all remaining DS1722 pins to VDD and GND. You can use available EM-X270 GPIOs to supply VDD and GND to DS1722. The following table summarizes the list of GPIOs used to supply VDD and GND to DS1722.

{|cellpadding="3" border="1" style="border: 1px solid rgb(85, 85, 85); border-collapse: collapse;"
| '''EM-X270 GPIO number''' || '''GPIO location''' || '''GPIO Functionality'''
|-
|22 || pin 10 of P2 connector on EM-X270 keypad extender || DS1722 GND
|-
|36 || pin 19 of P2 connector on EM-X270 keypad extender || DS1722 VDDD
|-
|96 || pin 8 of P2 connector on EM-X270 keypad extender || DS1722 VDDA
|-
|91 || pin 7 of P2 connector on EM-X270 keypad extender || DS1722 SERMOD
|-
|108 || pin 6 of P2 connector on EM-X270 keypad extender || DS1722 CE

|}

== SPI Sample ==
The SPI Sample performs the following actions:
* Configure the SPI clock frequency (5KHz) and SFRM signal polarity.
* Read the temperature measurement.
* Write to the DS1722 configuration register.
* Read back from the configuration register.

= SPI Driver =
== Overview ==
The Windows CE demo image includes the SPI driver, which allows direct access to SSP1 functionality. The SSP1 is also used to communicate with the evaluation kit LCD.

The EM-X270 SPI driver is a stream driver that may be accessed using the "SPI" prefix.

== SPI Driver API ==
=== Data Types ===
{{Struct | HeadLevel = ==== | Structname = SPI_SLAVE_CONFIG |
Description = Device configuration structure|
Field1 = DWORD dwDataSize |
Fieldexp1 = Size of each data frame in bits, allowed values: 4-32 |
Field2 = DWORD dwClockRate|
Fieldexp2 = Frequency in KHz. Allowed values: 4-13*1024 |
Field3 = [[#POLARITY|POLARITY]] ClockPol|
Fieldexp3 = Clock polarity |
Field4 = [[#POLARITY|POLARITY]] ChipSelectPol |
Fieldexp4 = SFRM polarity |
Field5 = BOOL bTxTristate |
Fieldexp5 = Tristate TX line when SFRM is de-asserted |
Field6 = BOOL ClkPhaseHalfCycle|
Fieldexp6 = TRUE - CLK remains in its inactive/idle state until one-half clock cycle after the SFRM signal is asserted at the beginning of a frame.<br>
FALSE - CLK remains in its inactive/idle state until one full clock cycle after the SFRM signal is asserted at the beginning of a frame.<br>
Meaningless when bCSExternal = TRUE |
Field7 = BOOL bCSExternal|
Fieldexp7 = SFRM is a GPIO |
Field8 = DWORD dwGpioNum|
Fieldexp8 = GPIO number for SFRM |
Remarks = bCSExternal is not supported in EM-X270|
}}
{{Struct | HeadLevel = ==== | Structname = SPITRANS|
Description = Transaction data|
Field1 = DWORD mTransactions |
Fieldexp1 = Number of data frames in the transaction|
Field2 = DWORD *mWriteBuffer |
Fieldexp2 = Data to be written to the port|
Field3 = DWORD *mReadBuffer |
Fieldexp3 = Data that was read from the port|
Field4 = | Field5 = | Field6 = | Field7 = | Field8 = |
Remarks = |
}}
{{Enum| HeadLevel = ==== | Enumname = POLARITY |
Description = Signals polarity enumeration|
Field1 = LOW_INACTIVE |
Field2 = HIGH_INACTIVE |
Field3 = |
Field4 = |
Remarks = |
}}
=== Functions ===
{{APIEx | HeadLevel = ==== | Signature = HANDLE SPIUserOpen() |
Description = Opens an instance of the SPI Bus Driver. |
Return = Returns a handle that should be used to access the driver. Nonzero indicates success. |
Param1 = |
Param2 = |
Param3 = |
Param4 = |
Remarks = }}

{{APIEx | HeadLevel = ==== | Signature = VOID SPIUserClose (HANDLE hDevice) |
Description = Closes the driver handle |
Return = |
Param1 = *hDevice - Handle to an open SPI bus instance|
Param2 = |
Param3 = |
Param4 = |
Remarks = }}

{{APIEx | HeadLevel = ==== | Signature = BOOL SPIUserSetConfiguration(HANDLE hDevice, [[#SPI_SLAVE_CONFIG|SPI_SLAVE_CONFIG]]* Settings) |
Description = Registers the configuration of the device.|
Return = TRUE - indicates success.|
Param1 = *hDevice - Handle to an open SPI bus instance|
Param2 = *Settings - The SPI device configuration|
Param3 = |
Param4 = |
Remarks = The device specific configuration is passed to the SPI controller internally in the driver immediately before transaction start. The driver keeps the configuration until between calls to this function or until the SPI bus handle is closed}}

{{APIEx | HeadLevel = ==== | Signature = BOOL SPIUserTransact (HANDLE hDevice, [[#SPITRANS|SPITRANS]]* pTrans) |
Description = Submits SPI data transaction to the target device |
Return = TRUE - indicates success.|
Param1 = *hDevice - Handle to an open SPI bus instance|
Param2 = *pTrans - pointer to data structures containing data buffers for the transaction
|
Param3 = |
Param4 = |
Remarks = The SPI transaction data buffers must be allocated and released by the user
}}

[[Category:Windows CE|SPI Sample ]]
[[Category:EM-X270|WinCE: SPI Sample ]]

EM-X270: WinCE: SPI Sample - Revision history

Kostyas at 16:18, 15 March 2010