lpcware

LPC812 SPI1 Master Clock and Chip Select Missing

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by Rorrik on Fri Oct 03 14:24:33 MST 2014
Using the following code to configure my SPI Master, I expect to see a 100 Kbs clock on P0_9, my sent signal on P0_15, and my chip select on P0_8.

        regVal = LPC_SWM->PINASSIGN4 & ~( 0xFFUL<<24 );
        LPC_SWM->PINASSIGN4 = regVal | ( 0x9<<24 );        //9 SCK
regVal = LPC_SWM->PIN  ASSIGN5 & ~( 0xFF<<0 );
LPC_SWM->PINASSIGN5 = regVal | ( 0xF<<0 );//15 MOSI
regVal = LPC_SWM->PINASSIGN5 & ~( 0xFF<<8 );
LPC_SWM->PINASSIGN5 = regVal | ( 0x11<<8 );//17 MISO
regVal = LPC_SWM->PINASSIGN5 & ~( 0xFF<<16 );
LPC_SWM->PINASSIGN5 = regVal | ( 0x8<<16 );//8 SSEL

        SPI_Init(LPC_SPI1, 0x7D, CFG_MASTER, DLY_PREDELAY(0)|DLY_POSTDELAY(0)|DLY_FRAMEDELAY(0)|DLY_INTERDELAY(0));

        message = (uint8_t *) TestSignal;
mSize = 2*sizeof(TestSignal) / sizeof(TestSignal[0]);

        SPI_Send( LPC_SPI1, CS_USED, message, mSize);

Probing each of these three pins, I see my test signal on pin P0_15 as expected, and the bit width is 10 microseconds as expected, corresponding to a clock period of 10 microseconds and a clock rate of 100 Kbs. However, I don't see a clock on P0_9 or the chip select on P0_8.

Any ideas what the problem could be? It should be noted that I am using SPI0 as a Slave and successfully receiving a signal from a master on pins 12, 13, and 14 before sending my master signal here.

Thanks!

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