CCS/EK-TM4C123GXL: ISSUE IN THE SPEED OF I2C IN TM4C123GH6PM

niranjan kumar85

Part Number: EK-TM4C123GXL
Other Parts Discussed in Thread: TM4C123GH6PM

Tool/software: Code Composer Studio

Hi all,

I am working with tiva for the past few month.Now i am using the ST l3g4200d gyroscope as slave for the TM4C123GH6PM controller.In these speed of I2c is very bad it not reaching 100kbps. I am using the system clock as in the API

SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ );

I2C clock is : I2CMasterInitExpClk (I2C2_BASE, SysCtlClockGet(), false); // In these i checked through datasheet i2c speed is 88kbps only

Due to these speed issue i am facing a problem while reading the gyroscope value and not getting the excepted value in the gyro.Can anyone provide a some tips to increase the speed of I2C.

NOTE:

PART NO: TM4C123GH6PM ,COMPILER : CCSv6

over 9 years ago

0 Bob Crosby over 9 years ago

TI__Guru 72500 points

What value was loaded into the I2CMTPR register? It should be 7, not 8.

0 cb1_mobile over 9 years ago in reply to Bob Crosby

Guru 117855 points

May I note that an "I2C" speed offset of 11% is UNLIKELY to cause failure to harvest "expected" values...

0 niranjan kumar85 over 9 years ago in reply to Bob Crosby

Prodigy 230 points

Thanks for the reply,
I noted the I2CMTPR register it was writing 7 only.I calculated manually now it 100Kbps and i have an another doubt.I want increase the speed further mean want i want to do,will you can guide mean..

0 Bob Crosby over 9 years ago in reply to niranjan kumar85

TI__Guru 72500 points

What speed do you want and what questions do you have? Have you considered using the PLL to operate at 80MHz system clock instead of 16MHz?

0 niranjan kumar85 over 9 years ago in reply to Bob Crosby

Prodigy 230 points

Thanks for reply,

Now my I2C is working fine by using the PLL @ 25MHZ

SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_25MHZ );

My I2CMTPR register writing 0x03 and my I2C speed is 312kbps.

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CCS/EK-TM4C123GXL: ISSUE IN THE SPEED OF I2C IN TM4C123GH6PM