SPI communication discussion

[ratheesht]

Hi,

       I have LPCXpresso 54102 LQFP64 Rev A (OM13077) development board & using LPCXpresso_8.1.0_597 IDE.

It is running with Cortex M4 processor at 96MHz.

I am executing the default example program "periph_spi_sm_int" to validate SPI protocol with master and slave.

After every transaction if i call the function setupMaster() then only it is working fine, otherwise it is giving wrong values. But for the general SPI communication this function( setupMaster() ) call is not required for every transmission of data because it is only needed at the time of initialization. So please suggest me your ideas whether it is required every time or not ?

I have submitted my queries already at below link, but i didnt get any result.

https://community.nxp.com/thread/447750 

[kerryzhou]

Hello Ratheesh T,

   Answer your two questions:

1. SPI can't receive the correct data in the periph_spi_sm_int sample code

Answer: The solution is  making SPI SLAVE IRQ has higher priority than master IRQ

Please add these codes before while(loop) : 
NVIC_SetPriority(LPC_SPIMASTERIRQNUM, 2);
NVIC_SetPriority(LPC_SPISLAVEIRQNUM, 1);
/* Enable SPI controller interrupts */
NVIC_EnableIRQ(LPC_SPIMASTERIRQNUM);
NVIC_EnableIRQ(LPC_SPISLAVEIRQNUM);

It just like this:

At last, the printf data is:

2. call the function setupMaster() 

Actually, just like the official code, you just need to call setupMaster() once, then you don't need to call it any more.

I have test it on my side, after add the item 1 code.

each time, I will get the correct data.

These are the three round test result:

SPI master/slave combined example

 SLAVE [txDoneCount = 17, rxDoneCount = 16]
 MASTER [txDoneCount = 16, rxDoneCount = 16]

TRANSFER COMPLETE: errors = 0
Master total transfer time = 17104uS
Showing data from : Master TX data
0x0001 0x0002 0x0003 0x0004 0x0005 0x0006 0x0007 0x0008
0x0009 0x000a 0x000b 0x000c 0x000d 0x000e 0x000f 0x0010
Showing data from : Master RX data
0xfffe 0xfffd 0xfffc 0xfffb 0xfffa 0xfff9 0xfff8 0xfff7
0xfff6 0xfff5 0xfff4 0xfff3 0xfff2 0xfff1 0xfff0 0xffef
Showing data from : Slave  TX data
0xfffe 0xfffd 0xfffc 0xfffb 0xfffa 0xfff9 0xfff8 0xfff7
0xfff6 0xfff5 0xfff4 0xfff3 0xfff2 0xfff1 0xfff0 0xffef
Showing data from : Slave  RX data
0x0001 0x0002 0x0003 0x0004 0x0005 0x0006 0x0007 0x0008
0x0009 0x000a 0x000b 0x000c 0x000d 0x000e 0x000f 0x0010

 SLAVE [txDoneCount = 17, rxDoneCount = 16]
 MASTER [txDoneCount = 16, rxDoneCount = 16]

TRANSFER COMPLETE: errors = 0
Master total transfer time = 17102uS
Showing data from : Master TX data
0x0011 0x0012 0x0013 0x0014 0x0015 0x0016 0x0017 0x0018
0x0019 0x001a 0x001b 0x001c 0x001d 0x001e 0x001f 0x0020
Showing data from : Master RX data
0xffee 0xffed 0xffec 0xffeb 0xffea 0xffe9 0xffe8 0xffe7
0xffe6 0xffe5 0xffe4 0xffe3 0xffe2 0xffe1 0xffe0 0xffdf
Showing data from : Slave  TX data
0xffee 0xffed 0xffec 0xffeb 0xffea 0xffe9 0xffe8 0xffe7
0xffe6 0xffe5 0xffe4 0xffe3 0xffe2 0xffe1 0xffe0 0xffdf
Showing data from : Slave  RX data
0x0011 0x0012 0x0013 0x0014 0x0015 0x0016 0x0017 0x0018
0x0019 0x001a 0x001b 0x001c 0x001d 0x001e 0x001f 0x0020

 SLAVE [txDoneCount = 17, rxDoneCount = 16]
 MASTER [txDoneCount = 16, rxDoneCount = 16]

TRANSFER COMPLETE: errors = 0
Master total transfer time = 17102uS
Showing data from : Master TX data
0x0021 0x0022 0x0023 0x0024 0x0025 0x0026 0x0027 0x0028
0x0029 0x002a 0x002b 0x002c 0x002d 0x002e 0x002f 0x0030
Showing data from : Master RX data
0xffde 0xffdd 0xffdc 0xffdb 0xffda 0xffd9 0xffd8 0xffd7
0xffd6 0xffd5 0xffd4 0xffd3 0xffd2 0xffd1 0xffd0 0xffcf
Showing data from : Slave  TX data
0xffde 0xffdd 0xffdc 0xffdb 0xffda 0xffd9 0xffd8 0xffd7
0xffd6 0xffd5 0xffd4 0xffd3 0xffd2 0xffd1 0xffd0 0xffcf
Showing data from : Slave  RX data
0x0021 0x0022 0x0023 0x0024 0x0025 0x0026 0x0027 0x0028
0x0029 0x002a 0x002b 0x002c 0x002d 0x002e 0x002f 0x0030

 SLAVE [txDoneCount = 17, rxDoneCount = 16]
 MASTER [txDoneCount = 16, rxDoneCount = 16]

TRANSFER COMPLETE: errors = 0
Master total transfer time = 17102uS
Showing data from : Master TX data
0x0031 0x0032 0x0033 0x0034 0x0035 0x0036 0x0037 0x0038
0x0039 0x003a 0x003b 0x003c 0x003d 0x003e 0x003f 0x0040
Showing data from : Master RX data
0xffce 0xffcd 0xffcc 0xffcb 0xffca 0xffc9 0xffc8 0xffc7
0xffc6 0xffc5 0xffc4 0xffc3 0xffc2 0xffc1 0xffc0 0xffbf
Showing data from : Slave  TX data
0xffce 0xffcd 0xffcc 0xffcb 0xffca 0xffc9 0xffc8 0xffc7
0xffc6 0xffc5 0xffc4 0xffc3 0xffc2 0xffc1 0xffc0 0xffbf
Showing data from : Slave  RX data
0x0031 0x0032 0x0033 0x0034 0x0035 0x0036 0x0037 0x0038
0x0039 0x003a 0x003b 0x003c 0x003d 0x003e 0x003f 0x0040

I also attached my modified code for your reference.

Wish it helps you!

Please try again, if you still have question, please let me know.

Have a great day,
Kerry

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[ratheesht]

Hi Kerry,

                After adding the priority , it is working &

thanks for your reply

[kerryzhou]

Hello Ratheesh T,

  You are welcome!

  If you have the new question, just create the new post.

Have a great day,
Kerry

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[ratheesht]

Hi Kerry Zhou,

                 In the above example project, i have removed the SPI slave.

That is LPC54102 board's SPI0 is acting as master mode only .i.e. LPC54102 have only master code . I have another one micro-controller which is acting as SLAVE.  

    When i am checking the  SPI communication with the above settings, it gives the same error which i have faced earlier.

i.e. For every transaction, if i call the function setupMaster(), then only it is working fine, otherwise it is giving wrong values.

Please let me know your suggestion, I am expecting your solution regarding this. 

[kerryzhou]

Hello Ratheesh T,

   If you use two LPC54102, one is master, and another one is SLAVE.

  Please try it like this, before the master power on, please power the SLAVE at first, then power the master later.

  Do this power on sequence is just make sure before the master send the data, the SLAVE MCU already initialized and it is read to receive the data from the SPI master.

   Please try it at first, please let me know!

Have a great day,
Kerry

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[ratheesht]

Hi Kerry,

             I am running LPC54102 board for Master mode and dialog micro-controller board for SPI  slave mode.

I don't have two LPC54102 micro-controller.So I have followed your power sequence suggestion in my SPI communication with LPC54102 as master and dialog MC as slave but it doesn't solve our problem.

[ratheesht]

Hi Kerry,

      Now it is working.

I have included delay after every frame of transmission and it is working. 

My question is

    Whether the delay is required in between every frame of transmission or not ?.

Please give me your suggestion 

[kerryzhou]

Hi Ratheesh T,

  Thank you for your updated information.

  I think you can check the SPI wave, wether the SPI slave already give out the correct data in the SPI bus when you don't add the delay. If the slave can give out the correct data, I don't think you need to add the delay in between every frame.

Have a great day,
Kerry

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