SCI port and I2C interface initialization for TMS570LS3137PGE

Yanzhong,

On SCI bus, you need to make sure that the data pins are in "high" state when there is active transfer. Would you please try the internal loopback mode to see if your software works?

I am not sure why you cannot access the registers. Can you send the complete project over for us to take a look?

Thanks and regards,

Zhaohong

Zhaohong,

I did try loop-back mode for the SCI. It did not work either.

I just double check the RX pin status during the data transmit and idle. It is High (pull-up enabled, otherwise it about 1.8V)

I am using IAR Embedded Workbench. So far, I just based on their "getting started" project and adding my portion.

There are 3 files: tms570ls3137_cstartup.s, low_level_init.C, main.C  (I did not touch the .s file)

I insert the files and IAR header file for TMS570LS3137PEG.

Yanzhong3201.570LS3137PGE_ThermoFisher.zip

Thanks,

Yanzhong

Yanzhong,

SCI TX should drive close to 3.3V when it is not transmitting. You may want to use a scope to see if it is changing over time.

It seems that the source code is constructed differently compared to TI compiler. I have two observations from the source code you sent.

(1) I did not not find a code section with initialize global variables. You may not use globals at all or they do not need to have initial values.

(2) For instructions as "CLKCNTRL_bit.PENA = 1U;", I am not sure how this data struct is defined to the correct address.

I would suggest the following.

(1) After running initialization, can you check if the system registers got the expected value using the memory display from the debugger? If the values are not correct, can you start initialization and check the register values after each write? If they are not correct, can you check the assembly instructions in the disassembly window and related CPU registers to see if the operation is correct?

(2) Do the same thing for SCI/LIN and I2C.

I would recommend replacing the instruction at address 0x0 with instruction "b #-8". This instruction holds CPU to address 0x0 after reset. When you connect debugger to CPU, you will see everything at default condition. This will make your debug session repeatable.

Thanks and regards,

Zhaohong

Zhaohong,

Thanks for the suggestion. I will look into it.

It's confused when comparing the codes in two different system.

I've sent the same files to IAR to see if they can catch something. will update you later.

Regards,

Yanzhong

Hi Zhaohong,

I finally figured out my problems.

For SCI port, the receiving actually was working, but cannot see the data in receiving regisiter in debug mode of IAR tool.

For I2C port, I think it's a bug of IAR tool. The defined I2C control registers as 16-bit registers.

Accoding to MCU ref manual, the I2C registers should be 32-bit registers with up 16-bit to be '0'.  (The manual is a little bit confusion there)

Thank you for your support anyway!

(sorry, I didn't know how to close the earier threads.)

Yanzhong

Hi Zhaohong,

I still need your help to take a look at my I2C initialization. - I still don't make it work yet.

Now, using 32bit register access, I can set the I2C registers. But I can not send data out - SCL pin does not have clock either.

(1) When MDR.STT (start condition) was set as '1', both SDA and SCL pins generated a "LOW" pulse.  (the 2 pins were pull-up to HIGH normally)

Below status flag bits were set to '1'

AL (bit0) = 1  (lost an arbitration ?)

TXRDY (bit4) = 1  (I2CDXR is empty)

XSMT (bit10) =1   (Transmit shift empty, no underflow has occurred)

BB (bit12) = 1 (the bus is busy)

(2) if I continued to write data to I2CDXR,  I can see I2CDXR has the data, but I can not see signals out at the SCL and SDA pins.

at the same time, TXRDY (bit4) changed to be '0'. But the rest AL, XSMT, BB still remained '1'.

My system has VCLK=59.904MHz.   I set Prescale =7   So, the module clock is 59.904/(7+1)=7.488MHz.

Then I set I2CCKL= 22, and I2CCLH=43, then I get the baud rate about 100K.

Below is my initialization code

  I2CMDR_bit.nIRS = 0;         

 I2CPSC = 0x00000007U; // set prescaler = 7   

 I2CCKL = 0x00000016U; // PLL option-1: 0x2D (45); PLL option-2: 0x16 (22)  

 I2CCKH = 0x0000002BU; // PLL option-1: 0x2C (44); PLL option-2: 0x2B (43)

  I2COAR = 0x0000007FU;  // Own Adder, bit-0 to bit6  

  I2CIMR = 0x00000000U;  // Interruption Mask Register ("1" = enable) - disable all interruptions  

  I2CSAR = 0x0000000EU; // Slave address: DAC (0x0E), I/O Exp1 (0x20), I/O Exp2 (0x24)     

 I2CPFNC = 0x00000000U;  // Use I2C function on SDA and SCL  

I2CPDR = 0x00000000U;   // enabled open-drain

I2CPDIS = 0x00000000U; // SDA and SCL pull function enabled  

 I2CPSEL = 0x00000003U; // SDA and SCL pull-up selected

 I2CMDR_bit.nIRS = 1;        // out of reset

    I2CMDR_bit.STB = 1;    //start byte enabled

    I2CMDR_bit.MST =1;     //master mode

    I2CMDR_bit.TRX = 1;     //transmit

   I2CMDR_bit.RM = 1;     // repeat mode

  I2CMDR_bit.STT = 1;     // set start condition - which generated "LOW" pulse on SDA and SCL pins. 

 I2CDXR = 0x00000055U;  // send data out

I had your sample code for I2C initialization, I did not see much different.

See if you can catch any thing or advice.

Thanks,

Yanzhong

Zhaohong,

The I2C port works now after I added external pull-up resistors for SDA and SCL - I thought the internal pull-up was enough to drive it.

So far, I can see clock and data sent out at Master and Transmit mode. But it stuck and the BB (bus busy) =1 - I thought it was not response from Slave.

I may still need some time to play around the hand shaking between the MCU and devices.

I'd like you to provide some explain about these  I2CMDR control bits

(1) STT (start condition) - as a Master and Transmit mode, it seems I have to set STT bit before sending a data byte.  Do I have to set STT=1 before each data byte send?

(2) STP (stop condition) - when do I suppose to use or set this bit?

(3) RM (repeat mode) - I set RM=1, but I can not send data continously.  (Does this because of the "BB=1"?)

(4) STB (start byte mode) - when set STB=1, does every send always using "00000001" to replace the salve address in  I2CSAR unitl STB is cleared to "0"?

(5) FREE (Free running bit) - what's the mean of "The I2C runs free" when set FREE = '1'.

Thanks,

Yanzhong

Zhaohong,

I just found that the address was sent out is from I2COAR, not from I2CSAR.

As I learnt, when FDF = 0, the Master transmit data with slave address which should be from I2CSAR.

I appreciate your help.  As I move forward, may bother you again. 

Yanzhong