Hello, I’m using Stream Buffers, in TASK A I’m receving data from UART and send this data to TASK B TASK A: ~~~ do{ nb = UARTReceive(&serialrxbuf[oldpos], portMAXDELAY); if (nb > 0){ newpos = PARSERCOMPLETE(serialrxbuf, oldpos+nb); if (newpos != -1){ count++; countnb += nb; if ((nb+oldpos) – newpos > 0){ if (xMessageBufferSpaceAvailable(serialreceivedatabuffer) < (nb+oldpos) – newpos){ // TODO: NOTIFY RECEPTION BUFFER FULL fullbuffercount++; fullbuffernbcount += nb; }else{ xMessageBufferSend(serialreceivedatabuffer,serialrxbuf,(nb+oldpos) – newpos, 0 ); } if (newpos > 0){ memcpy(serialrxbuf,&PRtstserialrxbuf[nb+oldpos-newpos],newpos); } } oldpos = newpos; }else{ // TODO: NOTIFY LOST RECEPTION oldpos = 0; // Reset Reception lostreception_count++; } } }while(1); ~~~ TASK B: ~~~ do{ datalength = xMessageBufferReceive(serialreceivedatabuffer, data, MAXDATARECEIVE,portMAXDELAY); if (datalength>0){ PARSER(data, data_length); } }while(1); ~~~ Sometimes xMessageBufferReceive continuously return 0. Is it possible??? Best Regards, Sergio

If I understand your question correctly, you are asking if it is possible for xMessageBufferReceive() to return 0 when portMAX_DELAY is used as the block time. If that is the case then that could conceivable happen if something is sending your task a direct to task notification while it is blocked on the message buffer. Does anything in your application use direct to task notifications, and if so, could such a notification be sent to the task that is blocked on the message buffer?

Hi, Yes this is my question. I don´t know why xMessageBufferReceive() return 0 with portMAX_DELAY used as the block time., and once it receives it, it never becomes blocked again. If something is sending to my task a direct to task notification, I’m not aware of that. How can it send “direct to task notifications”? In my Code I use other StreamBuffers, but this is only used in the atach code. Best Regards

Hi, Here more info: serialreceivedata_buffer is in 0x20014898 Before first call to xMessageBufferSend 0x20014898: ~~~ 00000000 00000000 00001399 00000001 20016948 00000000 200148BC 00000001 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 … ~~~ After the First call to xMessageBufferSend 0x20014898: ~~~ 00000000 0000008D 00001399 00000001 00000000 00000000 200148BC 00000001 00000000 00000089 0083024E F0313101 D0008006 02010007 06050403 0A090807 0E0D0C0B 1211100F 16151413 1A191817 1E1D1C1B 2221201F 26252423 2A292827 2E2D2C2B 3231302F 36353433 3A393837 3E3D3C3B 4241403F 46454443 4A494847 4E4D4C4B 5251504F 56555453 5A595857 5E5D5C5B 6261605F 66656463 6A696867 6E6D6C6B 7271706F 76757473 63797877 00000064 00000000 00000000 00000000 … ~~~ how can I interpret the first bytes of the structure? ~~~ 00000000 00000000 00001399 00000001 20016948 00000000 200148BC 00000001 00000000 00000000 ~~~ or ~~~ 00000000 0000008D 00001399 00000001 00000000 00000000 200148BC 00000001 00000000 00000089 ~~~ All Data insert to the StreamBuffer is like this: ~~~ 0012024E E5313101 D002AC0C 02010007 06050403 64330807 Header : 0x4E 0x02 Size : 0x00 0x12 —> 18bytes (Fixed + Variable Data) Fixed Data : 0x01 0x31 0x31 0xE5 0x0C 0xAC 0x02 0xD0 0x07 Variable Data: 0x00 0x01 0x02 0x03 0x04 0x05 0x06 0x07 0x08 CRC : 0x33 0x64 ~~~ The variable data is allways like this: ~~~ 0x00 0x01 … 0xFE 0xFF 0x00 0x01… ~~~ If the Program in running for a Time calling xMessageBufferSend and xMessageBufferReceive on a certain moment the xMessageBufferReceive start to return 0 allways and then: 0x20014898: ~~~ 00000DE2 00000072 00001399 00000001 00000000 00000000 200148BC 00000001 00000000 BDBCBBBA C1C0BFBE C5C4C3C2 C9C8C7C6 CDCCCBCA D1D0CFCE D5D4D3D2 D9D8D7D6 DDDCDBDA E1E0DFDE E5E4E3E2 E9E8E7E6 EDECEBEA F1F0EFEE F5F4F3F2 F9F8F7F6 FDFCFBFA 0100FFFE 05040302 09080706 0D0C0B0A 11100F0E 15141312 19181716 1D1C1B1A 21201F1E 25242322 29282726 D1D04463 D5D4D3D2 D9D8D7D6 DDDCDBDA E1E0DFDE E5E4E3E2 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04030201 08070605 0C0B0A09 100F0E0D 14131211 18171615 1C1B1A19 201F1E1D 24232221 28272625 2C2B2A29 302F2E2D 34333231 38373635 3C3B3A39 403F3E3D 44434241 48474645 4C4B4A49 504F4E4D 54535251 58575655 5C5B5A59 605F5E5D 64636261 68676665 6C6B6A69 706F6E6D 74737271 78777675 7C7B7A79 807F7E7D 84838281 88878685 8C8B8A89 908F8E8D 94939291 98979695 9C9B9A99 A09F9E9D A4A3A2A1 A8A7A6A5 ACABAAA9 B0AFAEAD B4B3B2B1 B8B7B6B5 BCBBBAB9 C0BFBEBD C4C3C2C1 C8C7C6C5 CCCBCAC9 D0CFCECD D4D3D2D1 D8D7D6D5 DCDBDAD9 E0DFDEDD E4E3E2E1 E8E7E6E5 ECEBEAE9 F0EFEEED F4F3F2F1 F8F7F6F5 FCFBFAF9 00FFFEFD 04030201 08070605 0C0B0A09 100F0E0D 14131211 18171615 1C1B1A19 201F1E1D 24232221 28272625 2C2B2A29 302F2E2D 34333231 38373635 3C3B3A39 403F3E3D 44434241 48474645 4C4B4A49 504F4E4D 54535251 58575655 5C5B5A59 605F5E5D 64636261 68676665 6C6B6A69 706F6E6D 74737271 78777675 7C7B7A79 807F7E7D 84838281 88878685 8C8B8A89 908F8E8D 94939291 98979695 9C9B9A99 A09F9E9D A4A3A2A1 A8A7A6A5 ACABAAA9 B0AFAEAD B4B3B2B1 B8B7B6B5 000000B9 20017CB4 00000308 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5 A5A5A5A5 … ~~~ This gives you some clue? Best Regards, Sergio

Sorry – don’t know what I am looking at in your last post.

Hi, I have only included more information about the Stream Buffer in case some of the internal information had been corrupted, since I do not know how to interpret the first bytes of StreamBuffer structure. If when I detect the problem (return 0):

• I check if there is space available in the buffer [xMessageBufferSpaceAvailable] I see that if there is space, and the buffer is not empty … but it keeps returning 0.
• I do a xMessageBufferReset everything works again until it happens again.

Best Regards Sergio

Have you stepped through the call in the debugger to see why it is returning 0?

Hi, My Mistake… the Size of Frame inserted with xMessageBufferSend was greater than xBufferLengthBytes Parameter in xMessageBufferReceive Thanks, Sergio