LMP90100 SPI Interface

vijaykumar sajjan

Other Parts Discussed in Thread: LMP90100

Hi ,

I am trying to communicate with LMP90100 through SPI with TM4C tiva controller,I will pasted my code below, I am trying to read a register 1F, but its not working .can u Help me where i am doing wrong

ROM_GPIOPinWrite(GPIO_PORTB_BASE,GPIO_PIN_5,0x00); //cs make it low

pui32DataTx[0]=0x90; // read register
pui32DataTx[1]=0x01; // ura

while(ROM_SSIBusy(SSI2_BASE)){}

ROM_SSIDataPut(SSI2_BASE,pui32DataTx[0]);
while(ROM_SSIBusy(SSI2_BASE)){}
ROM_SSIDataPut(SSI2_BASE,pui32DataTx[1]);
pui32DataTx[2]=0xAF; // read +2 bytes+LRA
while(ROM_SSIBusy(SSI2_BASE)){}
ROM_SSIDataPut(SSI2_BASE,pui32DataTx[2]);
while(ROM_SSIBusy(SSI2_BASE)){}
pui32DataTx[3]=0xff; // writing dummy byte
ROM_SSIDataPut(SSI2_BASE,pui32DataTx[3]);
while(ROM_SSIBusy(SSI2_BASE)){}
ROM_SSIDataGet(SSI2_BASE, &pui32DataRx[0]);
while(ROM_SSIBusy(SSI2_BASE)){}
ROM_GPIOPinWrite(GPIO_PORTB_BASE,GPIO_PIN_5,0xFF); //cs make disable(high)

UARTprintf("DATAFROM REGISTER = %d\n",pui32DataRx[0]);

over 9 years ago

0 vijaykumar sajjan over 9 years ago

Intellectual 390 points

now changed in code data width 8 to 16 , now also it is not working

u16DataTx=0x91;
u16DataTx= u16DataTx << 8;
u16DataTx |= 0xAF;

ROM_SSIDataPut(SSI2_BASE,u16DataTx);
while(ROM_SSIBusy(SSI2_BASE)){}
//ROM_SSIDataGet(SSI2_BASE, &u16DataRx);

UARTprintf("DATAFROM REGISTER = %d\n",(unsigned short)pui32DataRx[0]);

0 domenyko over 9 years ago

TI__Genius 9655 points

Hi Sajjan,

if your lines (quoted below),

pui32DataTx[0]=0x90; // read register
pui32DataTx[1]=0x01; // ura

refers the URA and in particular the first line is the INST1, it needs to be changed in

pui32DataTx[0]=0x10;

INST1 is always 0x10 for both writing and reading operations.

regards,

Domenico

0 vijaykumar sajjan over 9 years ago in reply to domenyko

Intellectual 390 points

Hi Domenico

Thanku ,

0 vijaykumar sajjan over 9 years ago in reply to vijaykumar sajjan

Intellectual 390 points

Hi Domenico.

As per your suggestion, i changed 0x90 to 0x10, now i am generating clock no problem, i am asserting and deserting, CS pin, SDO pin is showing same as CS select behaves . I was checking through Analyzer, But Data to SDI its not showing any thing what where I was wrighting, to transmitter pin its not going ,

0 domenyko over 9 years ago in reply to vijaykumar sajjan

TI__Genius 9655 points

Hi Sajjan,

please refer to the followng codes written for the MSP430 to check the sequence of your SPI command.

http://www.ti.com/lit/zip/snac029

regards,

Domenico

0 vijaykumar sajjan over 9 years ago in reply to domenyko

Intellectual 390 points

Hi Domenico,

Hi sorry for long gap, due to some other design work,

as per your suggestion, am able to write data means i saw in logic analyzer and i am getting clock pulse also . every thing working fine, when i will read from pertucular register i am not able to get that default value of the that register, is any register i have set before reading default values ,I am getting some constant value always . i referred what were you mentioned pdf,

0 vijaykumar sajjan over 9 years ago in reply to vijaykumar sajjan

Intellectual 390 points

Hi Domenico,

just i am reading data from registers but i am not getting default values from registers giving FF always

for reading data from register inst1 i used 0x90, in this time i got value like 104 etc, another case for reading data from register int1 0x10 used i got FF always the addres of register is 0x11 and the default value is 0x03,