Hi,
Last time I posted on this forum it proved to be very useful, so I'm hoping somebody might be able to assist again!
I am trying to make use of the included micro crystal for the CC430 - EM430F6137RF900 board.
I have soldered the crystal to pins of on port 5, P5.0 and P5.1. This is where I believe XIN and XOUT are also expected. I have included P5SEL |= 0x01,to select the XT1 function as outlined in the application note AN088.
I am using Simpliciti and have changed the Bsp_SetClocks method in bsp_board.c to the code included below and I wish to use the crystal for the ACLK.
The program gets stuck in the while loop suggesting there is a fault with XT1 in low frequency mode. I assume the crystal doesn't take longer than a second or even a few to stabilise, therefore I don't expect this to the problem (although correct me if I'm wrong!).
The code I have currently shows:
static void Bsp_SetClocks(void)
{
P5SEL |= 0x01;
UCSCTL6 &= ~(XT1OFF);
UCSCTL6 |= XCAP_3;
do{
UCSCTL7 &= ~XT1LFOFFG;
} while(UCSCTL7&XT1LFOFFG);
...
As I explained, the program loops in the while, suggesting a problem with the XT1 source. I also tried setting the register directly through hexadecimal as another check but had the same problem.
I'd be very grateful if anyone is able to see if there should be a problem here, to establish whether it is more likely I there is an issue with my crystal or connection to the board.
(I've also noticed in the user guide that the XT1BYPASS bit is set to 0 if XT1 is internal or 1 if an external pin is used. Is anyone able to clarify which this should be set to using an external crystal, I'm a little misled by using the term "bypass" given it is surely connected to an external pin?)
Thanks for any help in advance,
Richard
It has been a month... maybe you have solved the problem, maybe not. If you have, I'd like to hear how.
I have the CC430EM Boards, and I have basically the same problem. However, I have observed XT1 to settle sporadically -- sometimes it will work, and sometimes it will not. I was using Rev B chips in 2009, and I thought this was just a pre-release issue, but it seems to be a problem with the contemporary chips as well. I suppose it is also possible that the problem is not with the chip, but with the EM board, which has remained the same throughout -- it could be a capacitance mismatching issue, although I have tried fiddling with the optional cap settings with no resolution.
One workaround is to use the REF0CLK instead of XT1. It is also a 32768 Hz oscillator, but it is in the area of 2% precise, not 0.005% (50 ppm) like XT1. It may not be sufficient for deployment, but it does work rock solid(ly), and it suffices for testing. If you are using the RF in a very precise TDMA-style MAC, you will probably need XT1, though.
If the crystal you received with your board looks like this
Then solder it to the wires to pads 1 and 2 and the case to pad 3 as shown here
if your crystal look like this
Solder it to pads 1, 2, 3, and 4 as shown here with the beveled end towards the CC430 part
For both crystals, populate C541 and C551 with 12pF (0402 package type) capacitors.
This should get your crystal running.
Jim Noxon
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Thanks Jim,
JP,
As it happens I was indeed attempting to implement beaconing along with time allocated slots - just as an exercise. Unfortunately I never managed to find a solution and reverted back to using the REFOCLK. I won't be able to try what Jim suggested any time too soon but it'd be nice to hear if it worked for you.
Richard.
Gents,
we recently updated our MSP430F5xx/6xx/CC430 core libraries, which provide APIs for the PMM, clock (UCS), port, etc. modules for the devices. These function calls follow our recommended flow to bring up & configure the peripherals. Even though your code seems to be OK, I notice there are a couple of fault flags that are not being cleared. Try using the XT1 config function provided by the library.
Regards,
Dung
Hello, I use this similiar thread to my "problem".
I want to test functionality of Crystal 32kHz with EM430F6137rf900 board. I download newest MSP430ware_1_20_01_08 and try code cc430x613x_OF_LFXT1_nmi.c.
Description of code : LED is very fast (hm) blinking if crystal is not present, and LED is blinking for cca 1s if crystal is present. Its not working becasue LED without crystal is blinking with period 0.5s and with crystal is same time, but if I touch wires or crystal , led is shining about 2.5s . With Launchpad and MSP430G2553, and msp430g2xx3_LFxtal_nmi.c , the code working in common with description: Without crystal the LED is blinking very fast (cca 30 ms) and with crystal cca 1s.
Why is code for CC430 like working exapmle for launchpad? Is it bug or how I test XTAL with CC430 boards ? I cant add external cappacitors like is descripted above. Thanks, Michael