Recommended SPI-Prescaler Settings for TWR-MEM

[ScottKerstein]

Hello,

I'm using the TWR-K64 board, TWR-SER along with the TWR-MEM board in the Tower system.  What are the recommended SPI-prescaler settings to get the K64 to communicate with SPI Flash on the TWR-MEM board?

The TWR_MEM Jumpers for this chip are as follows: J-14(1-2) and J4(1-2).

Here are my software settings (Using KSDK 1.2.0):

    DSPI_HAL_SetDelay(m_pSpiBase[m_instance], (dspi_ctar_selection_t)configData.clkTransAtt, 0, 4, kDspiPcsToSck);

    DSPI_HAL_SetDelay(m_pSpiBase[m_instance], (dspi_ctar_selection_t)configData.clkTransAtt, 0, 4, kDspiLastSckToPcs);

    DSPI_HAL_SetDelay(m_pSpiBase[m_instance], (dspi_ctar_selection_t)configData.clkTransAtt, 0, 1, kDspiAfterTransfer);

    DSPI_HAL_SetContinuousSckCmd(m_pSpiBase[m_instance], SYS_FALSE);

configData.clkTransAtt  = SPI_CLK_TRANSFER_ATTRUBUTES configuration (below enumeration)

/*! @brief DSPI Clock and Transfer Attributes Register (CTAR) selection*/

typedef enum SPI_CLK_TRANSFER_ATTRUBUTES

{

    SPI_CLK_TRANSFER_ATTRUBUTES_MASTER_OR_SLAVE = 0,   /*!< CTAR0 selection option for master or slave mode */

    SPI_CLK_TRANSFER_ATTRUBUTES_MASTER,                /*!< CTAR1 selection option for master mode only */

    SPI_CLK_TRANSFER_ATTRUBUTES_EOL

} SpiClkTransferAttr_t;

Clock info from the Oscilloscope

kDspiPcsToSck = 614ns

kDspiLastSckToPcs = 614ns

Spec on this device is (min of 5ns)

Timing between clock cycles (rising edge to rising edge) is 2.074us

Spi Port Configurations are as follows:

PIN MUX

    #if(DEVELOPMENT_BOARD_TYPE==BLD_USING_TWRK64F120M_DEV_BOARD)

          BSP_PORT_PTD_PIN3, BSP_PORT_FUN_ALT_2 //SPI0_SIN  (MISO)

          BSP_PORT_PTD_PIN2, BSP_PORT_FUN_ALT_2 //SPI0_SOUT (MISO)

          BSP_PORT_PTD_PIN0, BSP_PORT_FUN_ALT_2 //SPI0_PCS0 (ChipSel)

          BSP_PORT_PTD_PIN1, BSP_PORT_FUN_ALT_2 //SPI0_SCLK (SpiClock)

    #endif

PORT/BUS: BSP_SPI_BUS_SPI_0

IRQ Priority: Normal

#if(DEVELOPMENT_BOARD_TYPE==BLD_USING_TWRK64F120M_DEV_BOARD)

{

    500000UL,                                     ///< U32 baudRate; in bps

   8,                                            ///< U8 bitsPerFrame; defines the frame size for the device transaction; range is 4 to 32

   false,                                        ///< BOOL contChipSelect; if set true, chip select always remains active (not useful)

    SPI_CLK_TRANSFER_ATTRUBUTES_MASTER_OR_SLAVE,  ///< SPI_CLK_TRANSFER_ATTRUBUTES_t clkTransAtt; Master or Master/slave role (CTAR0, or CTAR1)

   SPI_PCS0,                                     ///< SPI_PERIPHERIAL_CHIPSELECT_t peripheralCS; selection for the device chip select pin

    SPI_PCS_ACTIVE_LOW,                           ///< SPI_PERIPHERAL_CHIPSELECT_POLARITY_t polarityCS; shift polarity for the chip select pin

    SPI_CLOCK_POLARITY_ACTIVE_HIGH,               ///< SPI_CLOCK_POLARITY_t clkPolarity; clock polarity for the shift (idle state of SCLK)

    SPI_CLOCK_PHASE_LATCH_ON_LEADING_EDGE,        ///< SPI_CLOCK_PHASE_t clkPhase; clock phase for the shift;

                                                              -SPI_CLOCK_PHASE_LATCH_ON_LEADING_EDGE = command data is latched on leading edge of the clock pulse

    SPI_MSB_TRANSFER_FIRST,                       ///< SPI_SHIFT_DIRECTION_t shiftDirection; MSB or LSB first

},

#endif

Thanks, in advance.

Scott

[xiangjun_rong]

Hi, Scott,

Can you use the latest SDK2.1 or SDK2.0 package for the TWR-KV64? obviously, you use SDK1.3 currently, which is obsolete.

Regarding the SPI timing and the required prescaler, because you access the spi flash on the TWR-MEM, pls refer to the data sheet of spi flash in the following link. The maximum SPI clock frequency of reading flash is 30mHz, for example, I suppose you can set the SPI clock frequency as 10MHz, assume that the core/system clock frequency is 120MHz, bus clock frequency is 60mhz, you can set the PBR bits as 01(Baud Rate Prescaler value is 3.), BR as 00(Baud Rate Scaler Value), the spi sck baud rate is 60mHz/(3*2)=10MHz. Regarding the the other delay, pls refer to the data sheet  of the spi flash.

Hope it can help you

BR

Xiangjun Rong

spi flash data sheet of AT26DF081A-SU

http://www.atmel.com/Images/doc3600.pdf 

[xiangjun_rong]

Hi, Scott,

Can you give me a feedback and clarify your question?

BR

XiangJun Rong