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/**************************************************************************//**
* @file
* @brief EFM32GG_DK3750 board support package SPI API implementation
* @author Energy Micro AS
* @version 2.0.1
******************************************************************************
* @section License
* <b>(C) Copyright 2012 Energy Micro AS, http://www.energymicro.com</b>
*******************************************************************************
*
* Permission is granted to anyone to use this software for any purpose,
* including commercial applications, and to alter it and redistribute it
* freely, subject to the following restrictions:
*
* 1. The origin of this software must not be misrepresented; you must not
* claim that you wrote the original software.
* 2. Altered source versions must be plainly marked as such, and must not be
* misrepresented as being the original software.
* 3. This notice may not be removed or altered from any source distribution.
* 4. The source and compiled code may only be used on Energy Micro "EFM32"
* microcontrollers and "EFR4" radios.
*
* DISCLAIMER OF WARRANTY/LIMITATION OF REMEDIES: Energy Micro AS has no
* obligation to support this Software. Energy Micro AS is providing the
* Software "AS IS", with no express or implied warranties of any kind,
* including, but not limited to, any implied warranties of merchantability
* or fitness for any particular purpose or warranties against infringement
* of any proprietary rights of a third party.
*
* Energy Micro AS will not be liable for any consequential, incidental, or
* special damages, or any other relief, or for any claim by any third party,
* arising from your use of this Software.
*
*****************************************************************************/
/***************************************************************************//**
* @addtogroup BSP
* @{
******************************************************************************/
#include "efm32.h"
#include "em_gpio.h"
#include "em_usart.h"
#include "em_cmu.h"
#include "dvk.h"
#include "dvk_bcregisters.h"
/* USART used for SPI access */
#define USART_USED USART2 /**< USART used for BC register interface */
#define USART_CLK cmuClock_USART2 /**< Clock for BC register USART */
/* GPIO pins used, please refer to DVK user guide. */
#define PORT_SPI_TX gpioPortC /**< SPI transmit GPIO port */
#define PIN_SPI_TX 2 /**< SPI transmit GPIO pin */
#define PORT_SPI_RX gpioPortC /**< SPI receive GPIO port */
#define PIN_SPI_RX 3 /**< SPI receive GPIO pin */
#define PORT_SPI_CLK gpioPortC /**< SPI clock port */
#define PIN_SPI_CLK 4 /**< SPI clock pin */
#define PORT_SPI_CS gpioPortC /**< SPI Chip Select port */
#define PIN_SPI_CS 5 /**< SPI Chip Select pin */
static volatile const uint16_t *lastAddr = 0; /**< Last register accessed */
/**************************************************************************//**
* @brief Initializes SPI interface for access to board controller
* FPGA registers
*****************************************************************************/
static void SPI_BC_Init(void)
{
USART_InitSync_TypeDef bcinit = USART_INITSYNC_DEFAULT;
/* Enable module clocks */
CMU_ClockEnable(USART_CLK, true);
/* Configure SPI pins */
GPIO_PinModeSet(PORT_SPI_TX, PIN_SPI_TX, gpioModePushPull, 0);
GPIO_PinModeSet(PORT_SPI_RX, PIN_SPI_RX, gpioModeInput, 0);
GPIO_PinModeSet(PORT_SPI_CLK, PIN_SPI_CLK, gpioModePushPull, 0);
/* Keep CS high to not activate slave */
GPIO_PinModeSet(PORT_SPI_CS, PIN_SPI_CS, gpioModePushPull, 1);
/* Configure to use SPI master with manual CS */
/* For now, configure SPI for worst case 48MHz clock in order to work for all */
/* configurations. */
bcinit.refFreq = 48000000;
bcinit.baudrate = 7000000;
/* Initialize USART */
USART_InitSync(USART_USED, &bcinit);
/* Enable pins at default location */
USART_USED->ROUTE = USART_ROUTE_TXPEN | USART_ROUTE_RXPEN | USART_ROUTE_CLKPEN;
}
/**************************************************************************//**
* @brief Disables GPIO pins and USART from FPGA register access
*****************************************************************************/
static void SPI_BC_Disable(void)
{
/* Restore and disable USART */
USART_Reset(USART_USED);
GPIO_PinModeSet(PORT_SPI_TX, PIN_SPI_TX, gpioModeDisabled, 0);
GPIO_PinModeSet(PORT_SPI_RX, PIN_SPI_RX, gpioModeDisabled, 0);
GPIO_PinModeSet(PORT_SPI_CLK, PIN_SPI_CLK, gpioModeDisabled, 0);
GPIO_PinModeSet(PORT_SPI_CS, PIN_SPI_CS, gpioModeDisabled, 0);
/* Disable USART clock - we can't disable GPIO or HFPER as we don't know who else
* might be using it */
CMU_ClockEnable(USART_CLK, false);
}
/**************************************************************************//**
* @brief Perform SPI Transfer
* @param addr Register offset, starting at 0
* @param rw 0 on write, 1 on read accesses
* @param data 16-bit data to write into register/dummy data for reads
* @return 16-bit data received from SPI access
*****************************************************************************/
static uint16_t SPI_BC_Access(uint8_t addr, uint8_t rw, uint16_t data)
{
uint16_t tmp;
/* Enable CS */
GPIO_PinOutClear(PORT_SPI_CS, PIN_SPI_CS);
/* Write SPI address MSB */
USART_Tx(USART_USED, (addr & 0x3) | rw << 3);
/* Just ignore data read back */
USART_Rx(USART_USED);
/* Write SPI address LSB */
USART_Tx(USART_USED, data & 0xFF);
tmp = (uint16_t) USART_Rx(USART_USED);
/* SPI data MSB */
USART_Tx(USART_USED, data >> 8);
tmp |= (uint16_t) USART_Rx(USART_USED) << 8;
/* Disable CS */
GPIO_PinOutSet(PORT_SPI_CS, PIN_SPI_CS);
return tmp;
}
/**************************************************************************//**
* @brief Performs SPI write to FPGA register
* @param addr Address of register
* @param data Data to write
*****************************************************************************/
static void SPI_BC_Write(uint8_t addr, uint16_t data)
{
SPI_BC_Access(addr, 0, data);
}
/**************************************************************************//**
* @brief Performs SPI read from FPGA register
* @param addr Address of register
* @return 16-bit value of board controller register
*****************************************************************************/
static uint16_t SPI_BC_Read(uint8_t addr)
{
return SPI_BC_Access(addr, 1, 0);
}
/**************************************************************************//**
* @brief Initializes DVK register access
* @return true on success, false on failure
*****************************************************************************/
bool DVK_SPI_init(void)
{
uint16_t bcMagic;
/* Enable HF and GPIO clocks */
CMU_ClockEnable(cmuClock_HFPER, true);
CMU_ClockEnable(cmuClock_GPIO, true);
/* Configure SPI mode of operation */
DVK_busControlMode(DVK_BusControl_SPI);
SPI_BC_Init();
/* Read "board control Magic" register to verify SPI is up and running */
/* if not FPGA is configured to be in EBI mode */
bcMagic = DVK_SPI_readRegister(&BC_REGISTER->MAGIC);
if (bcMagic != BC_MAGIC_VALUE)
{
return false;
}
else
{
return true;
}
}
/**************************************************************************//**
* @brief Disable and free up resources used by SPI board control access
*****************************************************************************/
void DVK_SPI_disable(void)
{
SPI_BC_Disable();
}
/**************************************************************************//**
* @brief Perform read from DVK board control register
* @param[in] addr Address of register to read from
* @return Value of board controller register
*****************************************************************************/
uint16_t DVK_SPI_readRegister(volatile uint16_t *addr)
{
uint16_t data;
if (addr != lastAddr)
{
SPI_BC_Write(0x00, 0xFFFF & ((uint32_t) addr)); /*LSBs of address*/
SPI_BC_Write(0x01, 0xFF & ((uint32_t) addr >> 16)); /*MSBs of address*/
SPI_BC_Write(0x02, (0x0C000000 & (uint32_t) addr) >> 26); /*Chip select*/
}
/* Read twice; when register address has changed we need two SPI transfer
* to clock out valid data through board controller FIFOs */
data = SPI_BC_Read(0x03);
data = SPI_BC_Read(0x03);
lastAddr = addr;
return data;
}
/**************************************************************************//**
* @brief Perform write to DVK board control register
* @param addr Address of register to write to
* @param data 16-bit to write into register
*****************************************************************************/
void DVK_SPI_writeRegister(volatile uint16_t *addr, uint16_t data)
{
if (addr != lastAddr)
{
SPI_BC_Write(0x00, 0xFFFF & ((uint32_t) addr)); /*LSBs of address*/
SPI_BC_Write(0x01, 0xFF & ((uint32_t) addr >> 16)); /*MSBs of address*/
SPI_BC_Write(0x02, (0x0C000000 & (uint32_t) addr) >> 26); /*Chip select*/
}
SPI_BC_Write(0x03, data); /*Data*/
lastAddr = addr;
}
/** @} (end group BSP) */
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