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Diffstat (limited to 'source/lang')
| -rw-r--r-- | source/lang/api/hardwarespi.rst | 215 |
1 files changed, 108 insertions, 107 deletions
diff --git a/source/lang/api/hardwarespi.rst b/source/lang/api/hardwarespi.rst index 53a225d..289ded5 100644 --- a/source/lang/api/hardwarespi.rst +++ b/source/lang/api/hardwarespi.rst @@ -5,160 +5,161 @@ HardwareSPI =========== -This class is used for creating objects to manage the Maple's built-in -SPI ports. The Maple has two SPI ports. The relevant pins -corresponding to each port's logic signals are documented in the -following table (and on the Maple silkscreen): +This page describes how to use the built-in SPI ports. It does not +describe the SPI protocol itself. For more information about SPI, see +the :ref:`SPI reference <spi>`. -.. _lang-hardwarespi-pinout: +.. contents:: Contents + :local: -.. list-table:: - :header-rows: 1 +Getting Started +--------------- - * - Port number - - NSS - - MOSI - - MISO - - SCK +.. TODO [0.1.0] Add a note about calling disableDebugPorts() when +.. using SPI3 on Maple Native - * - 1 - - 10 - - 11 - - 12 - - 13 +In order to get started, you'll first need to define a ``HardwareSPI`` +variable, which you'll use to control the SPI port. Do this by +putting the line "``HardwareSPI spi(number);``" with your variables, +where ``number`` is the SPI port's number. - * - 2 - - 31 - - 32 - - 33 - - 34 +Here's an example (we'll fill in :ref:`setup() <lang-setup>` and +:ref:`loop() <lang-loop>` later):: -If you use a SPI port, you cannot simultaneously use its associated -pins for other purposes. + // Use SPI port number 1 + HardwareSPI spi(1); -Library Documentation ---------------------- + void setup() { + // Your setup code + } + + void loop() { + // Do stuff with SPI + } -Using the SPI Class -^^^^^^^^^^^^^^^^^^^ +Turning the SPI Port On +----------------------- -You can declare that you want to use SPI in your sketch by putting -``HardwareSPI Spi(number);`` with your variables, where ``number`` is -1 or 2, depending on which SPI you want to use. Then you can use the -functions described in the next section. For example:: +Now it's time to turn your SPI port on. Do this with the ``begin()`` +function (an example is given below). - // Use SPI 1 - HardwareSpi Spi(1); +.. FIXME [0.0.10] Breathe doesn't include the class; fix & submit pull req + +.. doxygenfunction:: HardwareSPI::begin + +The speed at which the SPI port communicates is configured using a +``SPIFrequency`` value: + +.. FIXME [0.1.0] Breathe's enum output is enormous; shrink & submit pull req + +.. doxygenenum:: SPIFrequency + +.. note:: Due to hardware issues, you can't use the frequency + ``SPI_140_625KHz`` with SPI port 1. + +You'll need to determine the correct values for ``frequency``, +``bitOrder``, and ``mode`` yourself, by consulting the datasheet for +the device you're communicating with. Continuing our example from +before, we'll add a call to ``begin()`` to our ``setup()``:: + + // Use SPI port number 1 + HardwareSPI spi(1); void setup() { - Spi.begin(SPI_18MHZ); + // Turn on the SPI port + spi.begin(SPI_18MHZ, MSBFIRST, 0); } void loop() { - // Get the next byte from the peripheral - uint8 byte = Spi.recv(); + // Do stuff with SPI } -HardwareSPI Class Reference -^^^^^^^^^^^^^^^^^^^^^^^^^^^ +If you call ``begin()`` with no arguments (as in "``spi.begin();``"), +it's the same as if you wrote "``spi.begin(SPI_1_125MHZ, MSBFIRST, +0);``". -.. cpp:class:: HardwareSPI +Communicating Over SPI +---------------------- - Class for interacting with SPI. +Now that you've got your SPI port set up, it's time to start +communicating. You can send data using ``HardwareSPI::write()``, +receive data using ``HardwareSPI::read()``, and do both using +``HardwareSPI::transfer()``. -.. cpp:function:: HardwareSPI::HardwareSPI(uint32 spi_num) +.. cpp:function:: void HardwareSPI::write(byte data) - Construct an object for managing a SPI peripheral. ``spi_num`` - must be 1 or 2; see the :ref:`table above - <lang-hardwarespi-pinout>` for pinout information. + Send a single byte of data. -.. cpp:function:: void HardwareSPI::begin(SPIFrequency freq, uint32 endianness, uint32 mode) + **Parameters**: - Configure the baudrate of the given SPI port and set up the header - pins appropriately. + - ``data``: Byte to send - Parameters: +.. cpp:function:: byte HardwareSPI::read() - - ``freq``: one of the ``SPIFrequency`` values, given :ref:`below - <lang-hardwarespi-spifrequency>`. + Get the next available, unread byte. If there aren't any unread + bytes, this function will wait until one is received. - - ``endianness``: either ``LSBFIRST`` (little-endian) or - ``MSBFIRST`` (big-endian). +.. cpp:function:: byte HardwareSPI::transmit(byte data) - - ``mode``: one of 0, 1, 2, or 3, and specifies which SPI mode is - used. The mode number determines a combination of polarity and - phase according to the following table: + Send a byte, then return the next byte received. - .. list-table:: - :header-rows: 1 + **Parameters:** - * - Mode - - Polarity - - Phase + - ``data``: Byte to send - * - 0 - - 0 - - 0 + **Returns:** Next unread byte - * - 1 - - 0 - - 1 +Continuing our example from before, let's send a number over SPI and +print out whatever we get back over :ref:`lang-serialusb`:: - * - 2 - - 1 - - 0 + // Use SPI port number 1 + HardwareSPI spi(1); - * - 3 - - 1 - - 1 + void setup() { + // Turn on the SPI port + spi.begin(SPI_18MHZ, MSBFIRST, 0); + } - For more information on polarity and phase, see the - :ref:`external references, below <lang-hardwarespi-seealso>`. + void loop() { + // Send 245 over SPI, and wait for a response. + spi.write(245); + byte response = spi.read(); + // Print out the response received. + SerialUSB.print("response: "); + SerialUSB.println(response, DEC); + } + +HardwareSPI Class Reference +--------------------------- + +There are a number of other things you can accomplish with your +``spi`` object. A full function listing follows. -.. cpp:function:: void HardwareSPI::begin() +.. doxygenclass:: HardwareSPI + :members: HardwareSPI, begin, beginSlave, end, read, write, transfer - A convenience ``begin()``, equivalent to ``begin(SPI_1_125MHZ, - MSBFIRST, 0)``. +Deprecated Functions +-------------------- -.. cpp:function:: uint8 HardwareSpi::send(uint8 *data, uint32 length) +The following functions are defined for now, but they have been +deprecated, and will be removed in a future Maple IDE release. You +shouldn't use them in new programs, and you should change any of your +programs which do use them to the up-to-date functions discussed +above. + +.. cpp:function:: uint8 HardwareSPI::send(uint8 *data, uint32 length) Writes ``data`` into the port buffer to be transmitted as soon as possible, where ``length`` is the number of bytes to send from ``data``. Returns the last byte shifted back from slave. -.. cpp:function:: uint8 HardwareSpi::send(uint8 data) +.. cpp:function:: uint8 HardwareSPI::send(uint8 data) Writes the single byte ``data`` into the port buffer to be transmitted as soon as possible. Returns the data byte shifted back from the slave. -.. cpp:function:: uint8 HardwareSpi::recv() +.. cpp:function:: uint8 HardwareSPI::recv() Reads a byte from the peripheral. Returns the next byte in the buffer. - -SPI Speeds -^^^^^^^^^^ - -.. _lang-hardwarespi-spifrequency: - -The possible SPI speeds are configured using the ``SPIFrequency`` enum: - -.. doxygenenum:: SPIFrequency - -.. _lang-hardwarespi-seealso: - -See Also --------- - -* `Wikipedia Article on Serial Peripheral Interface Bus (SPI) - <http://en.wikipedia.org/wiki/Serial_Peripheral_Interface_Bus>`_ -* `Arduino reference on SPI - <http://www.arduino.cc/playground/Code/Spi>`_ -* `Hardcore SPI on Arduino <http://klk64.com/arduino-spi/>`_ by kik64 -* STMicro documentation for STM32F103RB microcontroller: - - * `Datasheet <http://www.st.com/stonline/products/literature/ds/13587.pdf>`_ (pdf) - * `Reference Manual <http://www.st.com/stonline/products/literature/rm/13902.pdf>`_ (pdf) - - |