/**************************************************************************************************
* @fn mrfiSpiCmdStrobe
*
* @brief Send command strobe to the radio. Returns status byte read during transfer
* of strobe command.
*
* @param addr - address of register to strobe
*
* @return status byte of radio
**************************************************************************************************
*/
uint8_t mrfiSpiCmdStrobe(uint8_t addr)
{
uint8_t statusByte;
mrfiSpiIState_t s;
MRFI_SPI_ASSERT( MRFI_SPI_IS_INITIALIZED() ); /* SPI is not initialized */
MRFI_SPI_ASSERT((addr >= 0x30) && (addr <= 0x3D)); /* invalid address */
/* disable interrupts that use SPI */
MRFI_SPI_ENTER_CRITICAL_SECTION(s);
/* turn chip select "off" and then "on" to clear any current SPI access */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_TURN_CHIP_SELECT_ON();
/* send the command strobe, wait for SPI access to complete */
MRFI_SPI_WRITE_BYTE(addr);
MRFI_SPI_WAIT_DONE();
/* read the readio status byte returned by the command strobe */
statusByte = MRFI_SPI_READ_BYTE();
/* turn off chip select; enable interrupts that call SPI functions */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_EXIT_CRITICAL_SECTION(s);
/* return the status byte */
return(statusByte);
}
/*=================================================================================================
* @fn spiRegAccess
*
* @brief This function performs a read or write. The
* calling code must configure the read/write bit of the register's address byte.
* This bit is set or cleared based on the type of access.
*
* @param regAddrByte - address byte of register; the read/write bit already configured
*
* @return register value
*=================================================================================================
*/
static uint8_t spiRegAccess(uint8_t addrByte, uint8_t writeValue)
{
uint8_t readValue;
mrfiSpiIState_t s;
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
bool comm_state = sActiveSPI; // save comm state
#endif
MRFI_SPI_ASSERT( MRFI_SPI_IS_INITIALIZED() ); /* SPI is not initialized */
/* disable interrupts that use SPI */
MRFI_SPI_ENTER_CRITICAL_SECTION(s);
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
sActiveSPI = true; // indicate active comm state
#endif
/* turn chip select "off" and then "on" to clear any current SPI access */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_TURN_CHIP_SELECT_ON();
/* send register address byte, the read/write bit is already configured */
MRFI_SPI_WRITE_BYTE(addrByte);
MRFI_SPI_WAIT_DONE();
/*
* Send the byte value to write. If this operation is a read, this value
* is not used and is just dummy data. Wait for SPI access to complete.
*/
MRFI_SPI_WRITE_BYTE(writeValue);
MRFI_SPI_WAIT_DONE();
/*
* If this is a read operation, SPI data register now contains the register
* value which will be returned. For a read operation, it contains junk info
* that is not used.
*/
readValue = MRFI_SPI_READ_BYTE();
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
sActiveSPI = comm_state; // restore comm state
#endif
/* turn off chip select; enable interrupts that call SPI functions */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_EXIT_CRITICAL_SECTION(s);
/* return the register value */
return(readValue);
}
/**************************************************************************************************
* @fn mrfiSpiCmdStrobe
*
* @brief Send command strobe to the radio. Returns status byte read during transfer
* of strobe command.
*
* @param addr - address of register to strobe
*
* @return status byte of radio
**************************************************************************************************
*/
uint8_t mrfiSpiCmdStrobe(uint8_t addr)
{
uint8_t statusByte;
mrfiSpiIState_t s;
#ifdef DEBUG_SPI
DEBUG("SPI!C# ");
DEBUG_LN(cmdRegs[addr-SRES]);
#endif
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
bool comm_state = sActiveSPI; // save comm state
#endif
MRFI_SPI_ASSERT( MRFI_SPI_IS_INITIALIZED() ); /* SPI is not initialized */
MRFI_SPI_ASSERT((addr >= 0x30) && (addr <= 0x3D)); /* invalid address */
/* disable interrupts that use SPI */
MRFI_SPI_ENTER_CRITICAL_SECTION(s);
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
sActiveSPI = true; // indicate active comm state
#endif
/* turn chip select "off" and then "on" to clear any current SPI access */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_TURN_CHIP_SELECT_ON();
/* send the command strobe, wait for SPI access to complete */
MRFI_SPI_WRITE_BYTE(addr);
MRFI_SPI_WAIT_DONE();
/* read the readio status byte returned by the command strobe */
statusByte = MRFI_SPI_READ_BYTE();
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
sActiveSPI = comm_state; // restore comm state
#endif
/* turn off chip select; enable interrupts that call SPI functions */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_EXIT_CRITICAL_SECTION(s);
/* return the status byte */
return(statusByte);
}
/*=================================================================================================
* @fn spiRegAccess
*
* @brief This function performs a read or write. The
* calling code must configure the read/write bit of the register's address byte.
* This bit is set or cleared based on the type of access.
*
* @param regAddrByte - address byte of register; the read/write bit already configured
*
* @return register value
*=================================================================================================
*/
static uint8_t spiRegAccess(uint8_t addrByte, uint8_t writeValue)
{
uint8_t readValue;
mrfiSpiIState_t s;
MRFI_SPI_ASSERT( MRFI_SPI_IS_INITIALIZED() ); /* SPI is not initialized */
/* disable interrupts that use SPI */
MRFI_SPI_ENTER_CRITICAL_SECTION(s);
/* make sure clock phase and polarity are correct for radio */
MRFI_SPI_CLK_CONFIG();
/* turn chip select "off" and then "on" to clear any current SPI access */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_TURN_CHIP_SELECT_ON();
/* send register address byte, the read/write bit is already configured */
MRFI_SPI_WRITE_BYTE(addrByte);
MRFI_SPI_WAIT_DONE();
/*
* Send the byte value to write. If this operation is a read, this value
* is not used and is just dummy data. Wait for SPI access to complete.
*/
MRFI_SPI_WRITE_BYTE(writeValue);
MRFI_SPI_WAIT_DONE();
/*
* If this is a read operation, SPI data register now contains the register
* value which will be returned. For a write operation, it contains junk info
* that is not used.
*/
readValue = MRFI_SPI_READ_BYTE();
/* turn off chip select; enable interrupts that call SPI functions */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_EXIT_CRITICAL_SECTION(s);
/* return the register value */
return(readValue);
}
/*=================================================================================================
* @fn spiBurstFifoAccess
*
* @brief Burst mode access used for reading or writing to radio FIFOs.
*
* For more efficient interrupt latency, this function does not keep interrupts
* disabled for its entire execution. It is designed to recover if an interrupt
* occurs that accesses SPI. See comments in code for further details.
*
* @param addrByte - first byte written to SPI, contains address and mode bits
* @param pData - pointer to data to read or write
* @param len - length of data in bytes
*
* @return true if an interrupt was detected during the transfer, false otherwise
*=================================================================================================
*/
static bool spiBurstFifoAccess(uint8_t addrByte, uint8_t * pData, uint8_t len)
{
bool result = false; // initialize to successful status
mrfiSpiIState_t s;
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
bool comm_state = sActiveSPI; // save comm state
#endif
MRFI_SPI_ASSERT( MRFI_SPI_IS_INITIALIZED() ); /* SPI is not initialized */
MRFI_SPI_ASSERT(len != 0); /* zero length is not allowed */
MRFI_SPI_ASSERT(addrByte & BURST_BIT); /* only burst mode supported */
/* disable interrupts that use SPI */
MRFI_SPI_ENTER_CRITICAL_SECTION(s);
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
sActiveSPI = true; // indicate active comm state
#endif
/* turn chip select "off" and then "on" to clear any current SPI access */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_TURN_CHIP_SELECT_ON();
/*-------------------------------------------------------------------------------
* Main loop. If the SPI access is interrupted, execution comes back to
* the start of this loop. Loop exits when nothing left to transfer.
*/
do
{
/* send FIFO access command byte, wait for SPI access to complete */
MRFI_SPI_WRITE_BYTE(addrByte);
MRFI_SPI_WAIT_DONE();
/*-------------------------------------------------------------------------------
* Inner loop. This loop executes as long as the SPI access is not interrupted.
* Loop completes when nothing left to transfer.
*/
do
{
MRFI_SPI_WRITE_BYTE(*pData);
/*-------------------------------------------------------------------------------
* Use idle time. Perform increment/decrement operations before pending on
* completion of SPI access.
*
* Decrement the length counter. Wait for SPI access to complete.
*/
len--;
MRFI_SPI_WAIT_DONE();
/*-------------------------------------------------------------------------------
* SPI data register holds data just read. If this is a read operation,
* store the value into memory.
*/
if (addrByte & READ_BIT)
{
*pData = MRFI_SPI_READ_BYTE();
}
/*-------------------------------------------------------------------------------
* At least one byte of data has transferred. Briefly enable (and then disable)
* interrupts that can call SPI functions. This provides a window for any timing
* critical interrupts that might be pending.
*
* To improve latency, take care of pointer increment within the interrupt
* enabled window.
*/
MRFI_SPI_EXIT_CRITICAL_SECTION(s);
pData++;
MRFI_SPI_ENTER_CRITICAL_SECTION(s);
/*-------------------------------------------------------------------------------
* If chip select is "off" the SPI access was interrupted (all SPI access
* functions leave chip select in the "off" state). In this case, turn
* back on chip select and break to the main loop. The main loop will
* pick up where the access was interrupted.
*/
if (MRFI_SPI_CHIP_SELECT_IS_OFF())
{
MRFI_SPI_TURN_CHIP_SELECT_ON();
result = true; // indicate interruption detected
break;
}
/*-------------------------------------------------------------------------------
*/
} while (len); /* inner loop */
} while (len); /* main loop */
#ifdef MRFI_TIMER_ALWAYS_ACTIVE
sActiveSPI = comm_state; // restore comm state
#endif
/* turn off chip select; enable interrupts that call SPI functions */
MRFI_SPI_TURN_CHIP_SELECT_OFF();
MRFI_SPI_EXIT_CRITICAL_SECTION(s);
return result;
}