300 lines
10 KiB
C
300 lines
10 KiB
C
/**************************************************************************/
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/*!
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@file ssp.c
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@author K. Townsend (microBuilder.eu)
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@date 22 March 2010
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@version 0.10
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@section DESCRIPTION
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Generic code for SSP/SPI communications. By default, the SSP block
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is initialised in SPI master mode.
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@section Example
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@code
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#include "core/cpu/cpu.h"
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#include "core/ssp/ssp.h"
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...
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cpuInit();
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sspInit(0, sspClockPolarity_High, sspClockPhase_RisingEdge);
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...
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uint8_t request[SSP_FIFOSIZE];
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uint8_t response[SSP_FIFOSIZE];
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// Send 0x9C to the slave device and wait for a response
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request[0] = 0x80 | 0x1C;
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// Toggle the select pin
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ssp0Select();
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// Send 1 byte from the request buffer
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sspSend(0, (uint8_t *)&request, 1);
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// Receive 1 byte into the response buffer
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sspReceive(0, (uint8_t *)&response, 1);
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// Reset the select pin
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ssp0Deselect();
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// Print the results
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debug_printf("Ox%x ", response[0]);
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@endcode
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@section LICENSE
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Software License Agreement (BSD License)
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Copyright (c) 2010, microBuilder SARL
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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1. Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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3. Neither the name of the copyright holders nor the
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names of its contributors may be used to endorse or promote products
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derived from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ''AS IS'' AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/**************************************************************************/
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#include "ssp.h"
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#include "core/gpio/gpio.h"
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/* Statistics for all interrupts */
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volatile uint32_t interruptRxStat = 0;
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volatile uint32_t interruptOverRunStat = 0;
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volatile uint32_t interruptRxTimeoutStat = 0;
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/**************************************************************************/
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/*!
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@brief SSP0 interrupt handler for SPI communication
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The algorithm is, if RXFIFO is at least half full,
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start receive until it's empty; if TXFIFO is at least
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half empty, start transmit until it's full.
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This will maximize the use of both FIFOs and performance.
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*/
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/**************************************************************************/
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void SSP_IRQHandler (void)
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{
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uint32_t regValue;
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regValue = SSP_SSP0MIS;
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/* Check for overrun interrupt */
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if ( regValue & SSP_SSP0MIS_RORMIS_FRMRCVD )
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{
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interruptOverRunStat++;
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SSP_SSP0ICR = SSP_SSP0ICR_RORIC_CLEAR; // Clear interrupt
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}
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/* Check for timeout interrupt */
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if ( regValue & SSP_SSP0MIS_RTMIS_NOTEMPTY )
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{
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interruptRxTimeoutStat++;
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SSP_SSP0ICR = SSP_SSP0ICR_RTIC_CLEAR; // Clear interrupt
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}
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/* Check if Rx buffer is at least half-full */
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if ( regValue & SSP_SSP0MIS_RXMIS_HALFFULL )
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{
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// ToDo: Receive until it's empty
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interruptRxStat++;
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}
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return;
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}
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/**************************************************************************/
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/*!
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@brief Initialises the SSP0 port
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By default, SSP0 is set to SPI frame-format with 8-bit data. Pin 2.11
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is routed to serve as serial clock (SCK), and SSEL (0.2) is set to
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GPIO to allow manual control of when the SPI port is enabled or
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disabled. Overrun and timeout interrupts are both enabled.
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@param[in] portNum
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The SPI port to use (0..1)
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@param[in] polarity
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Indicates whether the clock should be held high
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(sspClockPolarity_High) or low (sspClockPolarity_Low)
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when inactive.
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@param[in] phase
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Indicates whether new bits start on the leading
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(sspClockPhase_RisingEdge) or falling
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(sspClockPhase_FallingEdge) edge of clock transitions.
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@note sspSelect() and sspDeselect() macros have been defined in
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ssp.h to control the SSEL line without having to know the
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specific pin being used.
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*/
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/**************************************************************************/
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void sspInit (uint8_t portNum, sspClockPolarity_t polarity, sspClockPhase_t phase)
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{
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gpioInit();
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if (portNum == 0)
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{
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/* Reset SSP */
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SCB_PRESETCTRL &= ~SCB_PRESETCTRL_SSP0_MASK;
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SCB_PRESETCTRL |= SCB_PRESETCTRL_SSP0_RESETDISABLED;
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/* Enable AHB clock to the SSP domain. */
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SCB_SYSAHBCLKCTRL |= (SCB_SYSAHBCLKCTRL_SSP0);
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/* Divide by 1 (SSPCLKDIV also enables to SSP CLK) */
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SCB_SSP0CLKDIV = SCB_SSP0CLKDIV_DIV1;
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/* Set P0.8 to SSP MISO */
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IOCON_PIO0_8 &= ~IOCON_PIO0_8_FUNC_MASK;
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IOCON_PIO0_8 |= IOCON_PIO0_8_FUNC_MISO0;
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/* Set P0.9 to SSP MOSI */
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IOCON_PIO0_9 &= ~IOCON_PIO0_9_FUNC_MASK;
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IOCON_PIO0_9 |= IOCON_PIO0_9_FUNC_MOSI0;
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/* Set 2.11 to SSP SCK (0.6 and 0.10 can also be used) */
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#ifdef CFG_SSP0_SCKPIN_2_11
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IOCON_SCKLOC = IOCON_SCKLOC_SCKPIN_PIO2_11;
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IOCON_PIO2_11 = IOCON_PIO2_11_FUNC_SCK0;
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#endif
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/* Set 0.6 to SSP SCK (2.11 and 0.10 can also be used) */
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#ifdef CFG_SSP0_SCKPIN_0_6
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IOCON_SCKLOC = IOCON_SCKLOC_SCKPIN_PIO0_6;
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IOCON_PIO0_6 = IOCON_PIO0_6_FUNC_SCK;
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#endif
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/* Set P0.2/SSEL to GPIO output and high */
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IOCON_PIO0_2 &= ~IOCON_PIO0_2_FUNC_MASK;
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IOCON_PIO0_2 |= IOCON_PIO0_2_FUNC_GPIO;
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gpioSetDir(SSP0_CSPORT, SSP0_CSPIN, 1);
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gpioSetValue(SSP0_CSPORT, SSP0_CSPIN, 1);
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gpioSetPullup(&IOCON_PIO0_2, gpioPullupMode_Inactive); // Board has external pull-up
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/* If SSP0CLKDIV = DIV1 -- (PCLK / (CPSDVSR <20> [SCR+1])) = (72,000,000 / (2 x [8 + 1])) = 4.0 MHz */
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uint32_t configReg = ( SSP_SSP0CR0_DSS_8BIT // Data size = 8-bit
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| SSP_SSP0CR0_FRF_SPI // Frame format = SPI
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| SSP_SSP0CR0_SCR_8); // Serial clock rate = 8
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// Set clock polarity
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if (polarity == sspClockPolarity_High)
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configReg |= SSP_SSP0CR0_CPOL_HIGH; // Clock polarity = High between frames
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else
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configReg &= ~SSP_SSP0CR0_CPOL_MASK; // Clock polarity = Low between frames
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// Set edge transition
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if (phase == sspClockPhase_FallingEdge)
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configReg |= SSP_SSP0CR0_CPHA_SECOND; // Clock out phase = Trailing edge clock transition
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else
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configReg &= ~SSP_SSP0CR0_CPHA_MASK; // Clock out phase = Leading edge clock transition
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// Assign config values to SSP0CR0
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SSP_SSP0CR0 = configReg;
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/* Clock prescale register must be even and at least 2 in master mode */
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SSP_SSP0CPSR = SSP_SSP0CPSR_CPSDVSR_DIV2;
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/* Clear the Rx FIFO */
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uint8_t i, Dummy=Dummy;
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for ( i = 0; i < SSP_FIFOSIZE; i++ )
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{
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Dummy = SSP_SSP0DR;
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}
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/* Enable the SSP Interrupt */
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NVIC_EnableIRQ(SSP_IRQn);
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/* Set SSPINMS registers to enable interrupts
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* enable all error related interrupts */
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SSP_SSP0IMSC = ( SSP_SSP0IMSC_RORIM_ENBL // Enable overrun interrupt
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| SSP_SSP0IMSC_RTIM_ENBL); // Enable timeout interrupt
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/* Enable device and set it to master mode, no loopback */
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SSP_SSP0CR1 = SSP_SSP0CR1_SSE_ENABLED | SSP_SSP0CR1_MS_MASTER | SSP_SSP0CR1_LBM_NORMAL;
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}
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return;
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}
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/**************************************************************************/
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/*!
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@brief Sends a block of data to the SSP0 port
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@param[in] portNum
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The SPI port to use (0..1)
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@param[in] buf
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Pointer to the data buffer
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@param[in] length
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Block length of the data buffer
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*/
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/**************************************************************************/
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void sspSend (uint8_t portNum, uint8_t *buf, uint32_t length)
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{
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uint32_t i;
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uint8_t Dummy = Dummy;
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if (portNum == 0)
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{
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for (i = 0; i < length; i++)
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{
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/* Move on only if NOT busy and TX FIFO not full. */
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while ((SSP_SSP0SR & (SSP_SSP0SR_TNF_NOTFULL | SSP_SSP0SR_BSY_BUSY)) != SSP_SSP0SR_TNF_NOTFULL);
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SSP_SSP0DR = *buf;
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buf++;
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while ( (SSP_SSP0SR & (SSP_SSP0SR_BSY_BUSY|SSP_SSP0SR_RNE_NOTEMPTY)) != SSP_SSP0SR_RNE_NOTEMPTY );
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/* Whenever a byte is written, MISO FIFO counter increments, Clear FIFO
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on MISO. Otherwise, when SSP0Receive() is called, previous data byte
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is left in the FIFO. */
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Dummy = SSP_SSP0DR;
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}
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}
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return;
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}
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/**************************************************************************/
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/*!
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@brief Receives a block of data from the SSP0 port
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@param[in] portNum
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The SPI port to use (0..1)
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@param[in] buf
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Pointer to the data buffer
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@param[in] length
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Block length of the data buffer
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*/
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/**************************************************************************/
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void sspReceive(uint8_t portNum, uint8_t *buf, uint32_t length)
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{
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uint32_t i;
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if (portNum == 0)
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{
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for ( i = 0; i < length; i++ )
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{
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/* As long as the receive FIFO is not empty, data can be received. */
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SSP_SSP0DR = 0xFF;
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/* Wait until the Busy bit is cleared */
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while ( (SSP_SSP0SR & (SSP_SSP0SR_BSY_BUSY|SSP_SSP0SR_RNE_NOTEMPTY)) != SSP_SSP0SR_RNE_NOTEMPTY );
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*buf = SSP_SSP0DR;
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buf++;
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}
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}
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return;
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}
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