How to the same DMA Stream with different DMA channel on the Cortex-M7(STM32F746)?
I want to use SPI2 and UART4 peripherals with DMA but, as I see DMA1-SPI2-Tx and DMA1-UART4-Tx uses the same dma stream.
SPI2_TX - DMA1_Stream4 (channel 0)
UART4_TX - DMA1_Stream4 (channel 4)
Is there any way to use the same DMA stream for the different peripherals at the same time?
microcontroller stm32 stm32f7
asked Nov 23 '18 at 12:58
erenbasturkerenbasturk
32527
add a comment |
I want to use SPI2 and UART4 peripherals with DMA but, as I see DMA1-SPI2-Tx and DMA1-UART4-Tx uses the same dma stream.
SPI2_TX - DMA1_Stream4 (channel 0)
UART4_TX - DMA1_Stream4 (channel 4)
Is there any way to use the same DMA stream for the different peripherals at the same time?
microcontroller stm32 stm32f7
asked Nov 23 '18 at 12:58
erenbasturkerenbasturk
32527
No the channel can't work for SPI and UART at the same time. Only thing you can do is use an additional handler which controls the access permission to the DMA channel if your system does not require using SPI and UART at exactly the same time.
– A.R.C.
Nov 23 '18 at 14:12
It is not a channel. Just the Stream are the sames, channells are different.
– erenbasturk
Nov 23 '18 at 19:44
add a comment |
I want to use SPI2 and UART4 peripherals with DMA but, as I see DMA1-SPI2-Tx and DMA1-UART4-Tx uses the same dma stream.
SPI2_TX - DMA1_Stream4 (channel 0)
UART4_TX - DMA1_Stream4 (channel 4)
Is there any way to use the same DMA stream for the different peripherals at the same time?
microcontroller stm32 stm32f7
asked Nov 23 '18 at 12:58
erenbasturkerenbasturk
32527
I want to use SPI2 and UART4 peripherals with DMA but, as I see DMA1-SPI2-Tx and DMA1-UART4-Tx uses the same dma stream.
SPI2_TX - DMA1_Stream4 (channel 0)
UART4_TX - DMA1_Stream4 (channel 4)
Is there any way to use the same DMA stream for the different peripherals at the same time?
microcontroller stm32 stm32f7
microcontroller stm32 stm32f7
asked Nov 23 '18 at 12:58
erenbasturkerenbasturk
32527
asked Nov 23 '18 at 12:58
erenbasturkerenbasturk
32527
asked Nov 23 '18 at 12:58
erenbasturkerenbasturk
32527
asked Nov 23 '18 at 12:58
erenbasturkerenbasturk
32527
asked Nov 23 '18 at 12:58
erenbasturkerenbasturk
32527
32527
No the channel can't work for SPI and UART at the same time. Only thing you can do is use an additional handler which controls the access permission to the DMA channel if your system does not require using SPI and UART at exactly the same time.
– A.R.C.
Nov 23 '18 at 14:12
It is not a channel. Just the Stream are the sames, channells are different.
– erenbasturk
Nov 23 '18 at 19:44
add a comment |
No the channel can't work for SPI and UART at the same time. Only thing you can do is use an additional handler which controls the access permission to the DMA channel if your system does not require using SPI and UART at exactly the same time.
– A.R.C.
Nov 23 '18 at 14:12
It is not a channel. Just the Stream are the sames, channells are different.
– erenbasturk
Nov 23 '18 at 19:44
No the channel can't work for SPI and UART at the same time. Only thing you can do is use an additional handler which controls the access permission to the DMA channel if your system does not require using SPI and UART at exactly the same time.
– A.R.C.
Nov 23 '18 at 14:12
No the channel can't work for SPI and UART at the same time. Only thing you can do is use an additional handler which controls the access permission to the DMA channel if your system does not require using SPI and UART at exactly the same time.
– A.R.C.
Nov 23 '18 at 14:12
It is not a channel. Just the Stream are the sames, channells are different.
– erenbasturk
Nov 23 '18 at 19:44
It is not a channel. Just the Stream are the sames, channells are different.
– erenbasturk
Nov 23 '18 at 19:44
add a comment |
1 Answer
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Is there any way to use the same DMA stream for the different peripherals at the same time?
No, there isn't. Only a single channel can be selected for each stream. Of course if you are not transmitting on both ports at the same time, then you can switch back and forth between channels.
Use another stream
Although it seems that both SPI2 TX and UART4 TX are confined to Stream 4, it is possible to control transmit channels by other means.
Note: this works only with SPI master or UART with no flow control. i.e. as long as the MCU is in complete control of the timing.
There is no rule saying that a DMA transfer should access the same peripheral the request came from (however they must be on the same APB bus for DMA1). It is possible to use e.g. TIM6 (or any other timer connected to DMA1) to generate periodic DMA requests on a stream other than 4, and set up that stream to transfer data from memory to SPI2->DR.
Just set the timer frequency to generate update DMA requests with 1/8 of your SPI bitrate, write a few bytes into SPI2->DR to fill the FIFO, and start the timer.
It would be more tricky with an UART with its various framing options, but it should generally work.
answered Nov 23 '18 at 14:54
berendiberendi
3,9511624
I will try to change the channell before the sending a data and see the latest status.
– erenbasturk
Nov 23 '18 at 19:43
add a comment |
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1 Answer
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oldest
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Is there any way to use the same DMA stream for the different peripherals at the same time?
No, there isn't. Only a single channel can be selected for each stream. Of course if you are not transmitting on both ports at the same time, then you can switch back and forth between channels.
Use another stream
Although it seems that both SPI2 TX and UART4 TX are confined to Stream 4, it is possible to control transmit channels by other means.
Note: this works only with SPI master or UART with no flow control. i.e. as long as the MCU is in complete control of the timing.
There is no rule saying that a DMA transfer should access the same peripheral the request came from (however they must be on the same APB bus for DMA1). It is possible to use e.g. TIM6 (or any other timer connected to DMA1) to generate periodic DMA requests on a stream other than 4, and set up that stream to transfer data from memory to SPI2->DR.
Just set the timer frequency to generate update DMA requests with 1/8 of your SPI bitrate, write a few bytes into SPI2->DR to fill the FIFO, and start the timer.
It would be more tricky with an UART with its various framing options, but it should generally work.
answered Nov 23 '18 at 14:54
berendiberendi
3,9511624
I will try to change the channell before the sending a data and see the latest status.
– erenbasturk
Nov 23 '18 at 19:43
add a comment |
Is there any way to use the same DMA stream for the different peripherals at the same time?
No, there isn't. Only a single channel can be selected for each stream. Of course if you are not transmitting on both ports at the same time, then you can switch back and forth between channels.
Use another stream
Although it seems that both SPI2 TX and UART4 TX are confined to Stream 4, it is possible to control transmit channels by other means.
Note: this works only with SPI master or UART with no flow control. i.e. as long as the MCU is in complete control of the timing.
There is no rule saying that a DMA transfer should access the same peripheral the request came from (however they must be on the same APB bus for DMA1). It is possible to use e.g. TIM6 (or any other timer connected to DMA1) to generate periodic DMA requests on a stream other than 4, and set up that stream to transfer data from memory to SPI2->DR.
Just set the timer frequency to generate update DMA requests with 1/8 of your SPI bitrate, write a few bytes into SPI2->DR to fill the FIFO, and start the timer.
It would be more tricky with an UART with its various framing options, but it should generally work.
answered Nov 23 '18 at 14:54
berendiberendi
3,9511624
I will try to change the channell before the sending a data and see the latest status.
– erenbasturk
Nov 23 '18 at 19:43
add a comment |
Is there any way to use the same DMA stream for the different peripherals at the same time?
No, there isn't. Only a single channel can be selected for each stream. Of course if you are not transmitting on both ports at the same time, then you can switch back and forth between channels.
Use another stream
Although it seems that both SPI2 TX and UART4 TX are confined to Stream 4, it is possible to control transmit channels by other means.
Note: this works only with SPI master or UART with no flow control. i.e. as long as the MCU is in complete control of the timing.
There is no rule saying that a DMA transfer should access the same peripheral the request came from (however they must be on the same APB bus for DMA1). It is possible to use e.g. TIM6 (or any other timer connected to DMA1) to generate periodic DMA requests on a stream other than 4, and set up that stream to transfer data from memory to SPI2->DR.
Just set the timer frequency to generate update DMA requests with 1/8 of your SPI bitrate, write a few bytes into SPI2->DR to fill the FIFO, and start the timer.
It would be more tricky with an UART with its various framing options, but it should generally work.
answered Nov 23 '18 at 14:54
berendiberendi
3,9511624
Is there any way to use the same DMA stream for the different peripherals at the same time?
No, there isn't. Only a single channel can be selected for each stream. Of course if you are not transmitting on both ports at the same time, then you can switch back and forth between channels.
Use another stream
Although it seems that both SPI2 TX and UART4 TX are confined to Stream 4, it is possible to control transmit channels by other means.
Note: this works only with SPI master or UART with no flow control. i.e. as long as the MCU is in complete control of the timing.
There is no rule saying that a DMA transfer should access the same peripheral the request came from (however they must be on the same APB bus for DMA1). It is possible to use e.g. TIM6 (or any other timer connected to DMA1) to generate periodic DMA requests on a stream other than 4, and set up that stream to transfer data from memory to SPI2->DR.
Just set the timer frequency to generate update DMA requests with 1/8 of your SPI bitrate, write a few bytes into SPI2->DR to fill the FIFO, and start the timer.
It would be more tricky with an UART with its various framing options, but it should generally work.
answered Nov 23 '18 at 14:54
berendiberendi
3,9511624
answered Nov 23 '18 at 14:54
berendiberendi
3,9511624
answered Nov 23 '18 at 14:54
berendiberendi
3,9511624
answered Nov 23 '18 at 14:54
berendiberendi
3,9511624
3,9511624
I will try to change the channell before the sending a data and see the latest status.
– erenbasturk
Nov 23 '18 at 19:43
add a comment |
I will try to change the channell before the sending a data and see the latest status.
– erenbasturk
Nov 23 '18 at 19:43
I will try to change the channell before the sending a data and see the latest status.
– erenbasturk
Nov 23 '18 at 19:43
I will try to change the channell before the sending a data and see the latest status.
– erenbasturk
Nov 23 '18 at 19:43
add a comment |
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No the channel can't work for SPI and UART at the same time. Only thing you can do is use an additional handler which controls the access permission to the DMA channel if your system does not require using SPI and UART at exactly the same time.
– A.R.C.
Nov 23 '18 at 14:12
It is not a channel. Just the Stream are the sames, channells are different.
– erenbasturk
Nov 23 '18 at 19:44