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Increase baseline SPI bulk transfer speeds #89

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Merged
merged 2 commits into from
Nov 18, 2019
Merged

Increase baseline SPI bulk transfer speeds #89

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7499b1a
Make the iomTransfer global to decrease single byte read/write time b…
Nov 15, 2019
14bb73b
Limit SPI max speed to HAL limit of 48MHz.
Nov 15, 2019
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27 changes: 16 additions & 11 deletions libraries/SPI/src/SPI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -28,6 +28,8 @@

const SPISettings DEFAULT_SPI_SETTINGS = SPISettings();

am_hal_iom_transfer_t iomTransfer = {0};

SPIClass::SPIClass(uint8_t iom_instance) : IOMaster(iom_instance)
{
_duplex = ap3_spi_full_duplex;
Expand Down Expand Up @@ -105,12 +107,25 @@ void SPIClass::begin()
}

config(DEFAULT_SPI_SETTINGS);

//Set global's settings that won't change between transfers
iomTransfer.ui32InstrLen = 0; // No instructions
iomTransfer.ui32Instr = 0; // No instructions
iomTransfer.bContinue = false;
iomTransfer.ui8RepeatCount = 0; // ?
iomTransfer.ui8Priority = 1; // ?
iomTransfer.ui32PauseCondition = 0; // ?
iomTransfer.ui32StatusSetClr = 0; // ?
}

void SPIClass::config(SPISettings settings)
{
memset((void *)&_config, 0x00, sizeof(am_hal_iom_config_t)); // Set the IOM configuration
_config.eInterfaceMode = AM_HAL_IOM_SPI_MODE;

if (settings.clockFreq > AM_HAL_IOM_MAX_FREQ)
settings.clockFreq = AM_HAL_IOM_MAX_FREQ;

_config.ui32ClockFreq = settings.clockFreq;
_config.eSpiMode = settings.dataMode;
_order = settings.bitOrder;
Expand Down Expand Up @@ -272,19 +287,9 @@ void SPIClass::transferIn(void *buf, size_t count)

void SPIClass::_transfer(void *buf_out, void *buf_in, size_t count)
{
am_hal_iom_transfer_t iomTransfer = {0};
// iomTransfer.uPeerInfo.ui32SpiChipSelect = cs_pad;
iomTransfer.ui32InstrLen = 0; // No instructions
iomTransfer.ui32Instr = 0; // No instructions
iomTransfer.ui32NumBytes = count; // How many bytes to transfer
// iomTransfer.eDirection = AM_HAL_IOM_TX; // AM_HAL_IOM_FULLDUPLEX - Note: Ambiq SDK says that FULLDUPLEX is not yet supported // todo:
iomTransfer.ui32NumBytes = count; // How many bytes to transfer
iomTransfer.pui32TxBuffer = (uint32_t *)buf_out; // todo: does this have the proper lifetime?
iomTransfer.pui32RxBuffer = (uint32_t *)buf_in;
iomTransfer.bContinue = false;
iomTransfer.ui8RepeatCount = 0; // ?
iomTransfer.ui8Priority = 1; // ?
iomTransfer.ui32PauseCondition = 0; // ?
iomTransfer.ui32StatusSetClr = 0; // ?

// Determine direction
if ((buf_out != NULL) && (buf_in != NULL))
Expand Down