LDMA - Linked DMA#
Linked Direct Memory Access (LDMA) Peripheral API.
LDMA API functions provide full support for the LDMA peripheral.
LDMA supports these DMA transfer types:
Memory to memory.
Memory to peripheral.
Peripheral to memory.
Peripheral to peripheral.
Constant value to memory.
LDMA supports linked lists of DMA descriptors allowing:
Circular and ping-pong buffer transfers.
Scatter-gather transfers.
Looped transfers.
LDMA has some advanced features:
Intra-channel synchronization (SYNC), allowing hardware events to pause and restart a DMA sequence.
Immediate-write (WRI), allowing DMA to write a constant anywhere in the memory map.
Complex flow control allowing if-else constructs.
Basic understanding of LDMA controller is assumed. Please refer to the reference manual for further details. The LDMA examples described in the reference manual are particularly helpful in understanding LDMA operations.
In order to use the DMA controller, the initialization function LDMA_Init() must have been executed once (normally during system initialization).
DMA transfers are initiated by a call to LDMA_StartTransfer(), transfer properties are controlled by the contents of LDMA_TransferCfg_t and LDMA_Descriptor_t structure parameters. The LDMA_Descriptor_t structure parameter may be a pointer to an array of descriptors, descriptors in array should be linked together as needed.
Transfer and descriptor initialization macros are provided for the most common transfer types. Due to the flexibility of LDMA peripheral, only a small subset of all possible initializer macros are provided, users should create new ones when needed.
Examples of LDMA usage:
A simple memory to memory transfer:
/* A single transfer of 4 half words. */
static const LDMA_TransferCfg_t transferCfg = LDMA_TRANSFER_CFG_MEMORY();
static const LDMA_Descriptor_t desc = LDMA_DESCRIPTOR_SINGLE_M2M_HALF(src, dst, 4);
void ldmaTransfer(void)
{
/* Initialize the LDMA with default values. */
LDMA_Init_t init = LDMA_INIT_DEFAULT;
LDMA_Init(&init);
/* Start the memory transfer */
LDMA_StartTransfer(0, &transferCfg, &desc);
}
A linked list of three memory to memory transfers:
/* A transfer consisting of 3 descriptors linked together and each descriptor
* transfers 4 words from the source to the destination. */
static const LDMA_TransferCfg_t transferCfg1 = LDMA_TRANSFER_CFG_MEMORY();
static const LDMA_Descriptor_t descList[] =
{
LDMA_DESCRIPTOR_LINKREL_M2M_WORD(src, dst, 4, 1),
LDMA_DESCRIPTOR_LINKREL_M2M_WORD(src + 4, dst + 4, 4, 1),
LDMA_DESCRIPTOR_SINGLE_M2M_WORD(src + 8, dst + 8, 4)
};
void ldmaLinkedTransfer(void)
{
/* Initialize the LDMA with default values. */
LDMA_Init_t init = LDMA_INIT_DEFAULT;
LDMA_Init(&init);
/* Start the linked memory transfer */
LDMA_StartTransfer(0, &transferCfg1, &descList[0]);
}
DMA from serial port peripheral to memory:
#if !defined(USART1) && defined(USART0)
/* The LDMA transfer should be triggered by the USART0 RX data available signal. */
static const LDMA_TransferCfg_t usart0RxTransfer =
LDMA_TRANSFER_CFG_PERIPHERAL(ldmaPeripheralSignal_USART0_RXDATAV);
/* Transfer 4 bytes from the USART0 RX FIFO to memory. */
static const LDMA_Descriptor_t usart0RxDesc =
LDMA_DESCRIPTOR_SINGLE_P2M_BYTE(&USART0->RXDATA, // Peripheral address
dst, // Destination (SRAM)
4); // Number of byte transfers
void ldmaPeripheralTransfer(void)
{
/* Initialize the LDMA with default values. */
LDMA_Init_t init = LDMA_INIT_DEFAULT;
LDMA_Init(&init);
/* Start the peripheral transfer which is triggered by the USART0
* peripheral RXDATAV signal. */
LDMA_StartTransfer(0, &usart0RxTransfer, &usart0RxDesc);
}
#elif defined(USART1)
/* The LDMA transfer should be triggered by the USART1 RX data available signal. */
static const LDMA_TransferCfg_t usart1RxTransfer =
LDMA_TRANSFER_CFG_PERIPHERAL(ldmaPeripheralSignal_USART1_RXDATAV);
/* Transfer 4 bytes from the USART1 RX FIFO to memory. */
static const LDMA_Descriptor_t usart1RxDesc =
LDMA_DESCRIPTOR_SINGLE_P2M_BYTE(&USART1->RXDATA, // Peripheral address
dst, // Destination (SRAM)
4); // Number of byte transfers
void ldmaPeripheralTransfer(void)
{
/* Initialize the LDMA with default values. */
LDMA_Init_t init = LDMA_INIT_DEFAULT;
LDMA_Init(&init);
/* Start the peripheral transfer which is triggered by the USART1
* peripheral RXDATAV signal. */
LDMA_StartTransfer(0, &usart1RxTransfer, &usart1RxDesc);
}
#elif defined(EUSART0)
/* The LDMA transfer should be triggered by the EUSART0 RX data available signal. */
static const LDMA_TransferCfg_t eusart0RxTransfer =
LDMA_TRANSFER_CFG_PERIPHERAL(ldmaPeripheralSignal_EUSART0_RXFL);
/* Transfer 4 bytes from the EUSART0 RX FIFO to memory. */
static const LDMA_Descriptor_t eusart0RxDesc =
LDMA_DESCRIPTOR_SINGLE_P2M_BYTE(&EUSART0->RXDATA, // Peripheral address
dst, // Destination (SRAM)
4); // Number of byte transfers
void ldmaPeripheralTransfer(void)
{
/* Initialize the LDMA with default values. */
LDMA_Init_t init = LDMA_INIT_DEFAULT;
LDMA_Init(&init);
/* Start the peripheral transfer which is triggered by the EUSART0
* peripheral RXFL signal. */
LDMA_StartTransfer(0, &eusart0RxTransfer, &eusart0RxDesc);
}
#endif
Ping-pong DMA from serial port peripheral to memory:
#if !defined(USART1) && defined(USART0)
/* Two buffers used in the ping-pong transfer from USART0. */
static volatile uint8_t buffer0[5];
static volatile uint8_t buffer1[5];
/* The LDMA transfer should be triggered by the USART0 RX data available signal. */
static const LDMA_TransferCfg_t usart0Transfer =
LDMA_TRANSFER_CFG_PERIPHERAL(ldmaPeripheralSignal_USART0_RXDATAV);
/* Both descriptors transfer 5 bytes from the USART0 rx data register into
* one of the buffers. Note that the first descriptor uses a relative address
* of 1 to link to the next descriptor, while the last descriptor uses a
* relative address of -1 to link to the first descriptor. */
static const LDMA_Descriptor_t rxLoop[] =
{
LDMA_DESCRIPTOR_LINKREL_P2M_BYTE(&USART0->RXDATA, buffer0, 5, 1),
LDMA_DESCRIPTOR_LINKREL_P2M_BYTE(&USART0->RXDATA, buffer1, 5, -1)
};
void ldmaPingPongTransfer(void)
{
/* Initialize the LDMA with default values. */
LDMA_Init_t init = LDMA_INIT_DEFAULT;
LDMA_Init(&init);
/* Start the peripheral transfer which is triggered by the USART0
* peripheral RXDATAV signal. */
LDMA_StartTransfer(0, &usart0Transfer, &rxLoop[0]);
}
#elif defined(USART1)
/* Two buffers used in the ping-pong transfer from USART1. */
static volatile uint8_t buffer0[5];
static volatile uint8_t buffer1[5];
/* The LDMA transfer should be triggered by the USART1 RX data available signal. */
static const LDMA_TransferCfg_t usart1Transfer =
LDMA_TRANSFER_CFG_PERIPHERAL(ldmaPeripheralSignal_USART1_RXDATAV);
/* Both descriptors transfer 5 bytes from the USART1 rx data register into
* one of the buffers. Note that the first descriptor uses a relative address
* of 1 to link to the next descriptor, while the last descriptor uses a
* relative address of -1 to link to the first descriptor. */
static const LDMA_Descriptor_t rxLoop[] =
{
LDMA_DESCRIPTOR_LINKREL_P2M_BYTE(&USART1->RXDATA, buffer0, 5, 1),
LDMA_DESCRIPTOR_LINKREL_P2M_BYTE(&USART1->RXDATA, buffer1, 5, -1)
};
void ldmaPingPongTransfer(void)
{
/* Initialize the LDMA with default values. */
LDMA_Init_t init = LDMA_INIT_DEFAULT;
LDMA_Init(&init);
/* Start the peripheral transfer which is triggered by the USART1
* peripheral RXDATAV signal. */
LDMA_StartTransfer(0, &usart1Transfer, &rxLoop[0]);
}
#elif defined(EUSART0)
/* Two buffers used in the ping-pong transfer from EUSART0. */
static volatile uint8_t buffer0[5];
static volatile uint8_t buffer1[5];
/* The LDMA transfer should be triggered by the EUSART0 RX data available signal. */
static const LDMA_TransferCfg_t eusart0Transfer =
LDMA_TRANSFER_CFG_PERIPHERAL(ldmaPeripheralSignal_EUSART0_RXFL);
/* Both descriptors transfer 5 bytes from the EUSART0 rx data register into
* one of the buffers. Note that the first descriptor uses a relative address
* of 1 to link to the next descriptor, while the last descriptor uses a
* relative address of -1 to link to the first descriptor. */
static const LDMA_Descriptor_t rxLoop[] =
{
LDMA_DESCRIPTOR_LINKREL_P2M_BYTE(&EUSART0->RXDATA, buffer0, 5, 1),
LDMA_DESCRIPTOR_LINKREL_P2M_BYTE(&EUSART0->RXDATA, buffer1, 5, -1)
};
void ldmaPingPongTransfer(void)
{
/* Initialize the LDMA with default values. */
LDMA_Init_t init = LDMA_INIT_DEFAULT;
LDMA_Init(&init);
/* Start the peripheral transfer which is triggered by the EUSART0
* peripheral RXFL signal. */
LDMA_StartTransfer(0, &eusart0Transfer, &rxLoop[0]);
}
#endif
Note
LDMA module does not implement LDMA interrupt handler. A template for an LDMA IRQ handler is included here as an example.
/* Template for an LDMA IRQ handler. */
void LDMA_IRQHandler(void)
{
uint32_t ch;
/* Get all pending and enabled interrupts. */
uint32_t pending = LDMA_IntGetEnabled();
/* Loop here on an LDMA error to enable debugging. */
while (pending & LDMA_IF_ERROR) {
}
/* Iterate over all LDMA channels. */
for (ch = 0; ch < DMA_CHAN_COUNT; ch++) {
uint32_t mask = 0x1 << ch;
if (pending & mask) {
/* Clear interrupt flag. */
#if defined (LDMA_HAS_SET_CLEAR)
LDMA->IF_CLR = mask;
#else
LDMA->IFC = mask;
#endif
/* Do more stuff here, execute callbacks etc. */
}
}
}
Modules#
Enumerations#
Controls the number of unit data transfers per arbitration cycle, providing a means to balance DMA channels' load on the controller.
DMA structure type.
DMA transfer block or cycle selector.
Source address increment unit size.
DMA transfer unit size.
Destination address increment unit size.
Source addressing mode.
Destination addressing mode.
DMA link load address mode.
Insert extra arbitration slots to increase channel arbitration priority.
Source address increment sign.
Destination address increment sign.
Peripherals that can trigger LDMA transfers.
Functions#
De-initialize the LDMA controller.
Enable or disable an LDMA channel request.
Initialize the LDMA controller.
Start a DMA transfer.
Stop a DMA transfer.
Check if a DMA transfer has completed.
Get the number of items remaining in a transfer.
Check if a certain channel is enabled.
Clear one or more pending LDMA interrupts.
Disable one or more LDMA interrupts.
Enable one or more LDMA interrupts.
Get pending LDMA interrupt flags.
Get enabled and pending LDMA interrupt flags.
Set one or more pending LDMA interrupts.
Macros#
Size in words of a non-extended DMA descriptor.
Size in words of an extended DMA descriptor.
Maximum transfer size possible per descriptor.
Converts a LDMA_Descriptor_t pointer to the value suitable to write to the linkAddr field of a LDMA_Descriptor_t.
Converts a LDMA_Descriptor_t linkAddr field value back to a LDMA_Descriptor_t pointer.
Default DMA initialization structure.
Generic DMA transfer configuration for memory to memory transfers.
Generic DMA transfer configuration for looped memory to memory transfers.
Generic DMA transfer configuration for memory to/from peripheral transfers.
Generic DMA transfer configuration for looped memory to/from peripheral transfers.
DMA descriptor initializer for single memory to memory word transfer.
DMA descriptor initializer for single memory to memory half-word transfer.
DMA descriptor initializer for single memory to memory byte transfer.
DMA descriptor initializer for linked memory to memory word transfer.
DMA descriptor initializer for linked memory to memory half-word transfer.
DMA descriptor initializer for linked memory to memory byte transfer.
DMA descriptor initializer for linked memory to memory word transfer.
DMA descriptor initializer for linked memory to memory half-word transfer.
DMA descriptor initializer for linked memory to memory byte transfer.
DMA descriptor initializer for byte transfers from a peripheral to memory.
DMA descriptor initializer for byte transfers from a peripheral to a peripheral.
DMA descriptor initializer for byte transfers from memory to a peripheral.
DMA descriptor initializer for byte transfers from a peripheral to memory.
DMA descriptor initializer for word transfers from a peripheral to memory.
DMA descriptor initializer for byte transfers from memory to a peripheral.
DMA descriptor initializer for Immediate WRITE transfer.
DMA descriptor initializer for Immediate WRITE transfer.
DMA descriptor initializer for Immediate WRITE transfer.
DMA descriptor initializer for SYNC transfer.
DMA descriptor initializer for SYNC transfer.
DMA descriptor initializer for SYNC transfer.
Enumeration Documentation#
LDMA_CtrlBlockSize_t#
LDMA_CtrlBlockSize_t
Controls the number of unit data transfers per arbitration cycle, providing a means to balance DMA channels' load on the controller.
Enumerator | |
---|---|
ldmaCtrlBlockSizeUnit1 | One transfer per arbitration. |
ldmaCtrlBlockSizeUnit2 | Two transfers per arbitration. |
ldmaCtrlBlockSizeUnit3 | Three transfers per arbitration. |
ldmaCtrlBlockSizeUnit4 | Four transfers per arbitration. |
ldmaCtrlBlockSizeUnit6 | Six transfers per arbitration. |
ldmaCtrlBlockSizeUnit8 | Eight transfers per arbitration. |
ldmaCtrlBlockSizeUnit16 | 16 transfers per arbitration. |
ldmaCtrlBlockSizeUnit32 | 32 transfers per arbitration. |
ldmaCtrlBlockSizeUnit64 | 64 transfers per arbitration. |
ldmaCtrlBlockSizeUnit128 | 128 transfers per arbitration. |
ldmaCtrlBlockSizeUnit256 | 256 transfers per arbitration. |
ldmaCtrlBlockSizeUnit512 | 512 transfers per arbitration. |
ldmaCtrlBlockSizeUnit1024 | 1024 transfers per arbitration. |
ldmaCtrlBlockSizeAll | Lock arbitration during transfer. |
127
of file platform/emlib/inc/em_ldma.h
LDMA_CtrlStructType_t#
LDMA_CtrlStructType_t
DMA structure type.
Enumerator | |
---|---|
ldmaCtrlStructTypeXfer | TRANSFER transfer type. |
ldmaCtrlStructTypeSync | SYNCHRONIZE transfer type. |
ldmaCtrlStructTypeWrite | WRITE transfer type. |
145
of file platform/emlib/inc/em_ldma.h
LDMA_CtrlReqMode_t#
LDMA_CtrlReqMode_t
DMA transfer block or cycle selector.
Enumerator | |
---|---|
ldmaCtrlReqModeBlock | Each DMA request trigger transfer of one block. |
ldmaCtrlReqModeAll | A DMA request trigger transfer of a complete cycle. |
152
of file platform/emlib/inc/em_ldma.h
LDMA_CtrlSrcInc_t#
LDMA_CtrlSrcInc_t
Source address increment unit size.
Enumerator | |
---|---|
ldmaCtrlSrcIncOne | Increment source address by one unit data size. |
ldmaCtrlSrcIncTwo | Increment source address by two unit data sizes. |
ldmaCtrlSrcIncFour | Increment source address by four unit data sizes. |
ldmaCtrlSrcIncNone | Do not increment source address. |
158
of file platform/emlib/inc/em_ldma.h
LDMA_CtrlSize_t#
LDMA_CtrlSize_t
DMA transfer unit size.
Enumerator | |
---|---|
ldmaCtrlSizeByte | Each unit transfer is a byte. |
ldmaCtrlSizeHalf | Each unit transfer is a half-word. |
ldmaCtrlSizeWord | Each unit transfer is a word. |
166
of file platform/emlib/inc/em_ldma.h
LDMA_CtrlDstInc_t#
LDMA_CtrlDstInc_t
Destination address increment unit size.
Enumerator | |
---|---|
ldmaCtrlDstIncOne | Increment destination address by one unit data size. |
ldmaCtrlDstIncTwo | Increment destination address by two unit data sizes. |
ldmaCtrlDstIncFour | Increment destination address by four unit data sizes. |
ldmaCtrlDstIncNone | Do not increment destination address. |
173
of file platform/emlib/inc/em_ldma.h
LDMA_CtrlSrcAddrMode_t#
LDMA_CtrlSrcAddrMode_t
Source addressing mode.
Enumerator | |
---|---|
ldmaCtrlSrcAddrModeAbs | Address fetched from a linked structure is absolute. |
ldmaCtrlSrcAddrModeRel | Address fetched from a linked structure is relative. |
181
of file platform/emlib/inc/em_ldma.h
LDMA_CtrlDstAddrMode_t#
LDMA_CtrlDstAddrMode_t
Destination addressing mode.
Enumerator | |
---|---|
ldmaCtrlDstAddrModeAbs | Address fetched from a linked structure is absolute. |
ldmaCtrlDstAddrModeRel | Address fetched from a linked structure is relative. |
187
of file platform/emlib/inc/em_ldma.h
LDMA_LinkMode_t#
LDMA_LinkMode_t
DMA link load address mode.
Enumerator | |
---|---|
ldmaLinkModeAbs | Link address is an absolute address value. |
ldmaLinkModeRel | Link address is a two's complement relative address. |
193
of file platform/emlib/inc/em_ldma.h
LDMA_CfgArbSlots_t#
LDMA_CfgArbSlots_t
Insert extra arbitration slots to increase channel arbitration priority.
Enumerator | |
---|---|
ldmaCfgArbSlotsAs1 | One arbitration slot selected. |
ldmaCfgArbSlotsAs2 | Two arbitration slots selected. |
ldmaCfgArbSlotsAs4 | Four arbitration slots selected. |
ldmaCfgArbSlotsAs8 | Eight arbitration slots selected. |
199
of file platform/emlib/inc/em_ldma.h
LDMA_CfgSrcIncSign_t#
LDMA_CfgSrcIncSign_t
Source address increment sign.
Enumerator | |
---|---|
ldmaCfgSrcIncSignPos | Increment source address. |
ldmaCfgSrcIncSignNeg | Decrement source address. |
207
of file platform/emlib/inc/em_ldma.h
LDMA_CfgDstIncSign_t#
LDMA_CfgDstIncSign_t
Destination address increment sign.
Enumerator | |
---|---|
ldmaCfgDstIncSignPos | Increment destination address. |
ldmaCfgDstIncSignNeg | Decrement destination address. |
213
of file platform/emlib/inc/em_ldma.h
LDMA_PeripheralSignal_t#
LDMA_PeripheralSignal_t
Peripherals that can trigger LDMA transfers.
Enumerator | |
---|---|
ldmaPeripheralSignal_NONE | No peripheral selected for DMA triggering. |
ldmaPeripheralSignal_LDMAXBAR_PRSREQ0 | Trigger on PRS REQ0. |
ldmaPeripheralSignal_LDMAXBAR_PRSREQ1 | Trigger on PRS REQ1. |
ldmaPeripheralSignal_TIMER0_CC0 | Trigger on TIMER0_CC0. |
ldmaPeripheralSignal_TIMER0_CC1 | Trigger on TIMER0_CC1. |
ldmaPeripheralSignal_TIMER0_CC2 | Trigger on TIMER0_CC2. |
ldmaPeripheralSignal_TIMER0_UFOF | Trigger on TIMER0_UFOF. |
ldmaPeripheralSignal_TIMER1_CC0 | Trigger on TIMER1_CC0. |
ldmaPeripheralSignal_TIMER1_CC1 | Trigger on TIMER1_CC1. |
ldmaPeripheralSignal_TIMER1_CC2 | Trigger on TIMER1_CC2. |
ldmaPeripheralSignal_TIMER1_UFOF | Trigger on TIMER1_UFOF. |
ldmaPeripheralSignal_USART0_RXDATAV | Trigger on USART0_RXDATAV. |
ldmaPeripheralSignal_USART0_RXDATAVRIGHT | Trigger on USART0_RXDATAVRIGHT. |
ldmaPeripheralSignal_USART0_TXBL | Trigger on USART0_TXBL. |
ldmaPeripheralSignal_USART0_TXBLRIGHT | Trigger on USART0_TXBLRIGHT. |
ldmaPeripheralSignal_USART0_TXEMPTY | Trigger on USART0_TXEMPTY. |
ldmaPeripheralSignal_USART1_RXDATAV | Trigger on USART1_RXDATAV. |
ldmaPeripheralSignal_USART1_RXDATAVRIGHT | Trigger on USART1_RXDATAVRIGHT. |
ldmaPeripheralSignal_USART1_TXBL | Trigger on USART1_TXBL. |
ldmaPeripheralSignal_USART1_TXBLRIGHT | Trigger on USART1_TXBLRIGHT. |
ldmaPeripheralSignal_USART1_TXEMPTY | Trigger on USART1_TXEMPTY. |
ldmaPeripheralSignal_I2C0_RXDATAV | Trigger on I2C0_RXDATAV. |
ldmaPeripheralSignal_I2C0_TXBL | Trigger on I2C0_TXBL. |
ldmaPeripheralSignal_I2C1_RXDATAV | Trigger on I2C1_RXDATAV. |
ldmaPeripheralSignal_I2C1_TXBL | Trigger on I2C1_TXBL. |
ldmaPeripheralSignal_PDM_RXDATAV | Trigger on PDM_RXDATAV. |
ldmaPeripheralSignal_IADC0_IADC_SCAN | Trigger on IADC0_IADC_SCAN. |
ldmaPeripheralSignal_IADC0_IADC_SINGLE | Trigger on IADC0_IADC_SINGLE. |
ldmaPeripheralSignal_MSC_WDATA | Trigger on MSC_WDATA. |
ldmaPeripheralSignal_TIMER2_CC0 | Trigger on TIMER2_CC0. |
ldmaPeripheralSignal_TIMER2_CC1 | Trigger on TIMER2_CC1. |
ldmaPeripheralSignal_TIMER2_CC2 | Trigger on TIMER2_CC2. |
ldmaPeripheralSignal_TIMER2_UFOF | Trigger on TIMER2_UFOF. |
ldmaPeripheralSignal_TIMER3_CC0 | Trigger on TIMER3_CC0. |
ldmaPeripheralSignal_TIMER3_CC1 | Trigger on TIMER3_CC1. |
ldmaPeripheralSignal_TIMER3_CC2 | Trigger on TIMER3_CC2. |
ldmaPeripheralSignal_TIMER3_UFOF | Trigger on TIMER3_UFOF. |
ldmaPeripheralSignal_TIMER4_CC0 | Trigger on TIMER4_CC0. |
ldmaPeripheralSignal_TIMER4_CC1 | Trigger on TIMER4_CC1. |
ldmaPeripheralSignal_TIMER4_CC2 | Trigger on TIMER4_CC2. |
ldmaPeripheralSignal_TIMER4_UFOF | Trigger on TIMER4_UFOF. |
ldmaPeripheralSignal_EUSART0_RXFL | Trigger on EUSART0_RXFL. |
ldmaPeripheralSignal_EUSART0_TXFL | Trigger on EUSART0_TXFL. |
253
of file platform/emlib/inc/em_ldma.h
Function Documentation#
LDMA_DeInit#
void LDMA_DeInit (void )
De-initialize the LDMA controller.
N/A |
LDMA interrupts are disabled and the LDMA clock is stopped.
80
of file platform/emlib/src/em_ldma.c
LDMA_EnableChannelRequest#
void LDMA_EnableChannelRequest (int ch, bool enable)
Enable or disable an LDMA channel request.
[in] | ch | LDMA channel to enable or disable requests. |
[in] | enable | If 'true', the request will be enabled. If 'false', the request will be disabled. |
Use this function to enable or disable an LDMA channel request. This will prevent the LDMA from proceeding after its current transaction if disabled.
117
of file platform/emlib/src/em_ldma.c
LDMA_Init#
void LDMA_Init (const LDMA_Init_t * init)
Initialize the LDMA controller.
[in] | init | A pointer to the initialization structure used to configure the LDMA. |
This function will disable all the LDMA channels and enable the LDMA bus clock in the CMU. This function will also enable the LDMA IRQ in the NVIC and set the LDMA IRQ priority to a user-configurable priority. The LDMA interrupt priority is configured using the LDMA_Init_t structure.
Note
Since this function enables the LDMA IRQ, always add a custom LDMA_IRQHandler to the application to handle any interrupts from LDMA.
142
of file platform/emlib/src/em_ldma.c
LDMA_StartTransfer#
void LDMA_StartTransfer (int ch, const LDMA_TransferCfg_t * transfer, const LDMA_Descriptor_t * descriptor)
Start a DMA transfer.
[in] | ch | A DMA channel. |
[in] | transfer | The initialization structure used to configure the transfer. |
[in] | descriptor | The transfer descriptor, which can be an array of descriptors linked together. Each descriptor's fields stored in RAM will be loaded into the certain hardware registers at the proper time to perform the DMA transfer. |
226
of file platform/emlib/src/em_ldma.c
LDMA_StopTransfer#
void LDMA_StopTransfer (int ch)
Stop a DMA transfer.
[in] | ch | A DMA channel to stop. |
Note
The DMA will complete the current AHB burst transfer before stopping.
403
of file platform/emlib/src/em_ldma.c
LDMA_TransferDone#
bool LDMA_TransferDone (int ch)
Check if a DMA transfer has completed.
[in] | ch | A DMA channel to check. |
Returns
True if transfer has completed, false if not.
432
of file platform/emlib/src/em_ldma.c
LDMA_TransferRemainingCount#
uint32_t LDMA_TransferRemainingCount (int ch)
Get the number of items remaining in a transfer.
[in] | ch | The channel number of the transfer to check. |
Note
This function does not take into account that a DMA transfer with a chain of linked transfers might be ongoing. It will only check the count for the current transfer.
Returns
A number of items remaining in the transfer.
471
of file platform/emlib/src/em_ldma.c
LDMA_ChannelEnabled#
bool LDMA_ChannelEnabled (int ch)
Check if a certain channel is enabled.
[in] | ch | LDMA channel to check. |
Returns
return true if the LDMA channel is enabled and false if the channel is not enabled.
2695
of file platform/emlib/inc/em_ldma.h
LDMA_IntClear#
void LDMA_IntClear (uint32_t flags)
Clear one or more pending LDMA interrupts.
[in] | flags | Pending LDMA interrupt sources to clear. Use one or more valid interrupt flags for the LDMA module. The flags are LDMA_IFC_ERROR and one done flag for each channel. |
2718
of file platform/emlib/inc/em_ldma.h
LDMA_IntDisable#
void LDMA_IntDisable (uint32_t flags)
Disable one or more LDMA interrupts.
[in] | flags | LDMA interrupt sources to disable. Use one or more valid interrupt flags for LDMA module. The flags are LDMA_IEN_ERROR and one done flag for each channel. |
2736
of file platform/emlib/inc/em_ldma.h
LDMA_IntEnable#
void LDMA_IntEnable (uint32_t flags)
Enable one or more LDMA interrupts.
[in] | flags | LDMA interrupt sources to enable. Use one or more valid interrupt flags for LDMA module. The flags are LDMA_IEN_ERROR and one done flag for each channel. |
Note
Depending on the use, a pending interrupt may already be set prior to enabling the interrupt. To ignore a pending interrupt, consider using LDMA_IntClear() prior to enabling the interrupt.
2755
of file platform/emlib/inc/em_ldma.h
LDMA_IntGet#
uint32_t LDMA_IntGet (void )
Get pending LDMA interrupt flags.
N/A |
Note
Event bits are not cleared by the use of this function.
Returns
LDMA interrupt sources pending. Returns one or more valid interrupt flags for LDMA module. The flags are LDMA_IF_ERROR and one flag for each LDMA channel.
2772
of file platform/emlib/inc/em_ldma.h
LDMA_IntGetEnabled#
uint32_t LDMA_IntGetEnabled (void )
Get enabled and pending LDMA interrupt flags.
N/A |
Useful for handling more interrupt sources in the same interrupt handler.
Note
Interrupt flags are not cleared by the use of this function.
Returns
Pending and enabled LDMA interrupt sources Return value is the bitwise AND of
the enabled interrupt sources in LDMA_IEN and
the pending interrupt flags LDMA_IF
2791
of file platform/emlib/inc/em_ldma.h
LDMA_IntSet#
void LDMA_IntSet (uint32_t flags)
Set one or more pending LDMA interrupts.
[in] | flags | LDMA interrupt sources to set to pending. Use one or more valid interrupt flags for LDMA module. The flags are LDMA_IFS_ERROR and one done flag for each LDMA channel. |
2808
of file platform/emlib/inc/em_ldma.h
Macro Definition Documentation#
LDMA_DESCRIPTOR_NON_EXTEND_SIZE_WORD#
#define LDMA_DESCRIPTOR_NON_EXTEND_SIZE_WORDValue:
4
Size in words of a non-extended DMA descriptor.
1088
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_EXTEND_SIZE_WORD#
#define LDMA_DESCRIPTOR_EXTEND_SIZE_WORDValue:
7
Size in words of an extended DMA descriptor.
1091
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_MAX_XFER_SIZE#
#define LDMA_DESCRIPTOR_MAX_XFER_SIZEValue:
(((_LDMA_CH_CTRL_XFERCNT_MASK >> _LDMA_CH_CTRL_XFERCNT_SHIFT) + 1))
Maximum transfer size possible per descriptor.
1094
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR#
#define LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDRValue:
(addr)
Converts a LDMA_Descriptor_t pointer to the value suitable to write to the linkAddr field of a LDMA_Descriptor_t.
1097
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKABS_LINKADDR_TO_ADDR#
#define LDMA_DESCRIPTOR_LINKABS_LINKADDR_TO_ADDRValue:
(linkAddr)
Converts a LDMA_Descriptor_t linkAddr field value back to a LDMA_Descriptor_t pointer.
1100
of file platform/emlib/inc/em_ldma.h
LDMA_INIT_DEFAULT#
#define LDMA_INIT_DEFAULTValue:
Default DMA initialization structure.
1107
of file platform/emlib/inc/em_ldma.h
LDMA_TRANSFER_CFG_MEMORY#
#define LDMA_TRANSFER_CFG_MEMORYValue:
Generic DMA transfer configuration for memory to memory transfers.
1128
of file platform/emlib/inc/em_ldma.h
LDMA_TRANSFER_CFG_MEMORY_LOOP#
#define LDMA_TRANSFER_CFG_MEMORY_LOOPValue:
Generic DMA transfer configuration for looped memory to memory transfers.
1150
of file platform/emlib/inc/em_ldma.h
LDMA_TRANSFER_CFG_PERIPHERAL#
#define LDMA_TRANSFER_CFG_PERIPHERALValue:
Generic DMA transfer configuration for memory to/from peripheral transfers.
1172
of file platform/emlib/inc/em_ldma.h
LDMA_TRANSFER_CFG_PERIPHERAL_LOOP#
#define LDMA_TRANSFER_CFG_PERIPHERAL_LOOPValue:
Generic DMA transfer configuration for looped memory to/from peripheral transfers.
1193
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_SINGLE_M2M_WORD#
#define LDMA_DESCRIPTOR_SINGLE_M2M_WORDValue:
DMA descriptor initializer for single memory to memory word transfer.
1208
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_SINGLE_M2M_HALF#
#define LDMA_DESCRIPTOR_SINGLE_M2M_HALFValue:
DMA descriptor initializer for single memory to memory half-word transfer.
1279
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_SINGLE_M2M_BYTE#
#define LDMA_DESCRIPTOR_SINGLE_M2M_BYTEValue:
DMA descriptor initializer for single memory to memory byte transfer.
1350
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKABS_M2M_WORD#
#define LDMA_DESCRIPTOR_LINKABS_M2M_WORDValue:
DMA descriptor initializer for linked memory to memory word transfer.
Link address must be an absolute address. Note
The linkAddr member of the transfer descriptor is not initialized. linkAddr must be initialized by using the proper bits right-shift to get the correct bits from the absolute address. LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR macro should be used for that operation:
desc.linkAddr = LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR(&next_desc);
The opposite bit shift (left) must be done with LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR if linkAddr is read.
1432
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKABS_M2M_HALF#
#define LDMA_DESCRIPTOR_LINKABS_M2M_HALFValue:
DMA descriptor initializer for linked memory to memory half-word transfer.
Link address must be an absolute address. Note
The linkAddr member of the transfer descriptor is not initialized. linkAddr must be initialized by using the proper bits right-shift to get the correct bits from the absolute address. LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR macro should be used for that operation:
desc.linkAddr = LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR(&next_desc);
The opposite bit shift (left) must be done with LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR if linkAddr is read.
1525
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKABS_M2M_BYTE#
#define LDMA_DESCRIPTOR_LINKABS_M2M_BYTEValue:
DMA descriptor initializer for linked memory to memory byte transfer.
Link address must be an absolute address. Note
The linkAddr member of the transfer descriptor is not initialized. linkAddr must be initialized by using the proper bits right-shift to get the correct bits from the absolute address. LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR macro should be used for that operation:
desc.linkAddr = LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR(&next_desc);
The opposite bit shift (left) must be done with LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR if linkAddr is read.
1618
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKREL_M2M_WORD#
#define LDMA_DESCRIPTOR_LINKREL_M2M_WORDValue:
DMA descriptor initializer for linked memory to memory word transfer.
Link address is a relative address. Note
The linkAddr member of the transfer descriptor is initialized to 4 (regular descriptor) or 7 (extended descriptor), assuming that the next descriptor immediately follows this descriptor (in memory).
1711
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKREL_M2M_HALF#
#define LDMA_DESCRIPTOR_LINKREL_M2M_HALFValue:
DMA descriptor initializer for linked memory to memory half-word transfer.
Link address is a relative address. Note
The linkAddr member of the transfer descriptor is initialized to 4 (regular descriptor) or 7 (extended descriptor), assuming that the next descriptor immediately follows this descriptor (in memory).
1804
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKREL_M2M_BYTE#
#define LDMA_DESCRIPTOR_LINKREL_M2M_BYTEValue:
DMA descriptor initializer for linked memory to memory byte transfer.
Link address is a relative address. Note
The linkAddr member of the transfer descriptor is initialized to 4 (regular descriptor) or 7 (extended descriptor), assuming that the next descriptor immediately follows this descriptor (in memory).
1897
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_SINGLE_P2M_BYTE#
#define LDMA_DESCRIPTOR_SINGLE_P2M_BYTEValue:
DMA descriptor initializer for byte transfers from a peripheral to memory.
1979
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_SINGLE_P2P_BYTE#
#define LDMA_DESCRIPTOR_SINGLE_P2P_BYTEValue:
DMA descriptor initializer for byte transfers from a peripheral to a peripheral.
2050
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_SINGLE_M2P_BYTE#
#define LDMA_DESCRIPTOR_SINGLE_M2P_BYTEValue:
DMA descriptor initializer for byte transfers from memory to a peripheral.
2083
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKREL_P2M_BYTE#
#define LDMA_DESCRIPTOR_LINKREL_P2M_BYTEValue:
DMA descriptor initializer for byte transfers from a peripheral to memory.
2163
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKREL_P2M_WORD#
#define LDMA_DESCRIPTOR_LINKREL_P2M_WORDValue:
DMA descriptor initializer for word transfers from a peripheral to memory.
2244
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKREL_M2P_BYTE#
#define LDMA_DESCRIPTOR_LINKREL_M2P_BYTEValue:
DMA descriptor initializer for byte transfers from memory to a peripheral.
2325
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_SINGLE_WRITE#
#define LDMA_DESCRIPTOR_SINGLE_WRITEValue:
DMA descriptor initializer for Immediate WRITE transfer.
2404
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKABS_WRITE#
#define LDMA_DESCRIPTOR_LINKABS_WRITEValue:
DMA descriptor initializer for Immediate WRITE transfer.
Link address must be an absolute address. Note
The linkAddr member of the transfer descriptor is not initialized. linkAddr must be initialized by using the proper bits right-shift to get the correct bits from the absolute address. LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR should be used for that operation:
desc.linkAddr = LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR(&next_desc);
The opposite bit shift (left) must be done with LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR if linkAddr is read.
2447
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKREL_WRITE#
#define LDMA_DESCRIPTOR_LINKREL_WRITEValue:
DMA descriptor initializer for Immediate WRITE transfer.
2484
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_SINGLE_SYNC#
#define LDMA_DESCRIPTOR_SINGLE_SYNCValue:
DMA descriptor initializer for SYNC transfer.
2518
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKABS_SYNC#
#define LDMA_DESCRIPTOR_LINKABS_SYNCValue:
DMA descriptor initializer for SYNC transfer.
Link address must be an absolute address. Note
The linkAddr member of the transfer descriptor is not initialized. linkAddr must be initialized by using the proper bits right-shift to get the correct bits from the absolute address. LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR should be used for that operation:
desc.linkAddr = LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR(&next_desc);
The opposite bit shift (left) must be done with LDMA_DESCRIPTOR_LINKABS_ADDR_TO_LINKADDR if linkAddr is read.
2565
of file platform/emlib/inc/em_ldma.h
LDMA_DESCRIPTOR_LINKREL_SYNC#
#define LDMA_DESCRIPTOR_LINKREL_SYNCValue:
DMA descriptor initializer for SYNC transfer.
2606
of file platform/emlib/inc/em_ldma.h