hi how to implement fifo with usart in stm32f0308

[SSRIN.2]

Iam new to stm32 microcontrollers, i have to read uart continuously and store to array. and size of the data received from uart is variable. if i use the fifo with uart i can solve problem.

so please help me how program to receive data from uart in fifo

[Andrew Neil]

"Iam new to stm32 microcontrollers"

Do you have any experience with any other microcontroller(s) ?

Did you mean STM32F030x8?

Datasheet has no mention of any hardware FIFO for the USART:

So you'd have to implement any FIFO (aka "Ring Buffer" or "Circular Buffer") in software.

Since it's in software, it wouldn't be specific to the STM32 - there are plenty of general resources on implementing circular buffers

https://www.google.com/search?q=circular+buffer+fifo

[SSRIN.2]

thank you for response

[SSRIN.2]

"Do you have any experience with any other microcontroller(s) ?"

actually i have worked on esp32

now i am working on stm32, i mainly deal with uart in stm32f0308. in that i have to receive data different length of data like 13bytes and 15 bytes and 20 bytes continuously.

now iam facing problem with this concept

[Tesla DeLorean]

Does the data packet contain information that infers size, or do you have to track arrival of burst of data? What is the packet format or protocol?

So is the problem one of "parsing" the data stream? Can you create a stateful processing of the data? ie a state machine that interprets the bytes as they arrive, re-synchronizes if necessary and extract an length or checksum/integrity.

Ring-Buffers are pretty basic concept in any computing field. So perhaps some school/college level texts?

[SSRIN.2]

could you please suggest me how to tackle this

[Andrew Neil]

@SSRIN.2​  "stm32f0308"

Again, that's not a proper part number - please give the actual part number

 

"could you please suggest me how to tackle this"

Yes, a Ring Buffer - aka "Circular Buffer" or FIFO - is a standard approach.

Did you follow the link I gave earlier?

[SSRIN.2]

here iam using HAL_UART_Receive_DMA(&huart1, rxbuff,20)

here if iam receiving 20 bytes continuously it is working fine. but in between 13 bytes and 15 bytes received data is overwrite happens

[KnarfB]

here is a good reference https://github.com/MaJerle/stm32-usart-uart-dma-rx-tx

hth

KnarfB

[SSRIN.2]

@Andrew Neil​ 

''Again, that's not a proper part number - please give the actual part number''

part number is STM32F030R8T6

[SSRIN.2]

actuall when i press button controller sends bytes like ee b1 10 00 01 00 01 1b 01 ff fc ff ff

when i press button each time i receive bytes like this ee b1 10 00 01 00 01 1b 01 ff fc ff ff

i have to copy above bytes to an array and compare.

some times i receive 15 byets and 20 bytes.

here 13bytes data is ee b1 10 00 01 00 01 1b 01 ff fc ff ff

15 bytes data is EE B1 10 00 01 00 04 11 10 00 00 3D FF FC FF FF

20 BYTES DATA IS EE B1 10 00 01 00 08 11 E5 48 00 F0 BF 6B 5F 5F FF FC FF FF FF

whatever the size i receive i have store like location 0 to location 19

if 20 bytes received means i have to store like this

ARR[0]=EE

ARR[1]=B1

ARR[2]=10

ARR[3]=00

ARR[4]=01

ARR[5]=00

ARR[6]=08

ARR[7]=11

ARR[8]=E5

ARR[9]=48

ARR[10]=00

ARR[11]=F0

ARR[12]=BF

ARR[13]=6B

ARR[14]=5F

ARR[15]=5F

ARR[16]=FF

ARR[17]=FC

ARR[18]=FF

ARR[19]=FF

if 15 bytes received in same array it should store like this

ARR[0]=EE

ARR[1]=B1

ARR[2]=10

ARR[3]=00

ARR[4]=01

ARR[5]=00

ARR[6]=04

ARR[7]=11

ARR[8]=10

ARR[9]=00

ARR[10]=00

ARR[11]=36

ARR[12]=FF

ARR[13]=FC

ARR[14]=FF

ARR[15]=FF

please help me to tackle above

[Tesla DeLorean]

Fill the array in a byte-wise fashion, using ARR[6] byte, as it arrives, to determine the overall length of the packet, and how many bytes remain to complete the frame.

As each frame is completed move it to a holding buffer for processing whilst you continue to collect data for the next frame.

[SSRIN.2]

can you please suggest me any example code

[Johi]

Or you use the fifo's in the UART or you use DMA, both together can create trouble.

Now problem with DMA can be that you do not know how many bytes you are about to receive. Therefore, for uart there is   HAL_UARTEx_ReceiveToIdle_DMA(m_pUart, m_dmaRxBuf, UART_RX_BUF_SIZE); receive to idle does what it says: receive until idle is detected on your UART. Using this will save you the trouble created by various lengths.

Best regards,

Johi.

[Andrew Neil]

@Johi​  "use the fifo's in the UART"

Does an STM32F030R8T6 have any FIFOs in the UART?

[SSRIN.2]

"how to implement fifo with usart in stm32f0308"

Hi,

for above uart problem solved, I used IDLE DMA UART RECEPTION, in this data reception with different sizes is resolved

i used HAL_UARTEx_ReceiveToIdle_DMA for data reception.

but in this, data reception UART stops suddenly. i didnt understand why this happening

please help me how to solve this "UART STOPS RECEIVE DATA". if we reset device it starts working

[Andrew Neil]

@SSRIN.2​ "above uart problem solved"

That's good - now please mark the solution (see below).

"please help me how to solve this "UART STOPS RECEIVE DATA"

It seems you've started a separate thread on that:

https://community.st.com/s/question/0D53W00001gvnRhSAI/hi-everyonewhy-uart-using-dma-stops-receiving-data-suddenly-in-idle-mode