I don't understand why you are testing OFIFG when really, XT2 is all you
are interested in. After reading the (Write only)docs, I have come to
the conclusion that the method I am using for XT@ stabilization will
work fine (and is faster).
Here's what I'm using:
unsigned long int templong; // Doesn't have to be long
// ***** Wait for SMCLK to report no error
port2.out.pin5 = 1; // set a bit for test
FLL_CTL1 &= ~XT2OFF; // clear bit = high freq xtal on
templong = 50000; // loop until flag is clear
while ( FLL_CTL0 & XT2OF ) // test high freq osc fault flag
if ( !( templong-- ) )
{// Timeout waiting for XT2
// Tell the user about xt2
// error and deal w/ it (code removed)
}
port2.out.pin5 = 0; // clear that bit
Using my scope, it shows this taking about 6.245ms with Fxt2 of 8Mhz.
This sounds about right to me. According to the docs, OFIFG is a
confusing bit. The manual clearly states: "The OFIFG oscillator-fault
flag is set and latched at POR or when an oscillator fault (LFOF, XT1OF,
XT2OF, DCOF set) is detected.". So, by testing this bit, you are
actually checking all the oscillators, not just the XT2 Osc. Check out
the example from TI labeled fet440_clks2.c (part of slac019.zip). I
realize this is for the FET440, but the osc's work the same. This
example is a bit confusing because B Merritt has decided to consume more
current by writing to a read-only bit. That's why I came up w/ this
code. The docs also state that these bits are automatically cleared by
Hardware, so there is no need to manually clear them. I am also unsure
of the desire to simply sit around and wait for a bunch of clock cycles
and then test the flag. Seems to me, you want to get things going. If
you want to wait some time after the osc is going, then do that after it
goes clear, not arbitrarily.
Any thoughts?
Enjoy
-Mark
Ti's examples can be found here:
http://focus.ti.com/analog/docs/analoggencontent.tsp?templateId=5246&nav
igationId=10032&familyId=342&path=templatedata/cm/general/data/200209msp
430codeexamples
Or, go here: http://www.ti.com/msp430 and click on Design Resources
(left bar) and then Code examples.
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Harry
Lemmens
Sent: Wednesday, June 18, 2003 8:20 PM
To: [email protected]
Subject: RE: [Mspgcc-users] Re: MSP430F149 & RF RS232 help...
You cannot switch directly to SMCLK after turning on XT2. You must wait
in a
loop testing the oscillator flag. Even after this flag indicates the
oscillator is running, you must wait some time as the osc is still
"bouncing" around in level as it stabilises.
The following I posted several days ago. It is not optimal, but it does
seem
to get around most HF oscillator problems in an MSP430F149. (in fact,
the
code is fairly messy)
// attach HF crystal (8.000MHz) to XT2IN/OUT
BCSCTL1 &= ~XT2OFF ; // enable xtl2
do //wait in loop until crystal is stable
{
IFG1 &= ~OFIFG;
} while(OFIFG & IFG1);
// But, the osc has only indicated that it is running, instability is
still
possible in fact, seen it all the time in prototypes! so ...
NeedHFXTAL:
for (TimeFix = 0; TimeFix < 2048; TimeFix++) // osc bit
indicated ok, now
give another few thousand cycles to stabilise
{
IFG1 &= ~OFIFG; // continuously reset the osc fault flag
}
if ( (IFG1 & OFIFG) ) goto NeedHFXTAL; // osc fault flag is
still set
BCSCTL2 = SELM_2 | DIVM_0 | SELS | DIVS_0; // This is 0x88,
MCLK & SMCLK
to XTL2
The only problem with the above is that failure of the HF oscillator
will
cause the code above to freeze in an infinite loop. Maybe a loop count
should be added, and beyond a certain amount of tries, some fault flag
should be set.
Cheers
Harry
-----Original Message-----
From: [email protected]
[mailto:[email protected]]on Behalf Of helick
Sent: Thursday, June 19, 2003 4:29 AM
To: [email protected]
Subject: [Mspgcc-users] Re: MSP430F149 & RF RS232 help...
Oi Pedro,
Obrigado por responder.
Don't worry about the previous code I posted, I mis-read something and
ACLK should not have been used since I don't have an external clock
source, it's SMCLK now...
The problem I am having now is that I cannot detect any signals coming
out
of
TXBUF0. I plugged it in a logic analyser and nothing comes out.
Bellow is my setup() function. I don't quite know what might be wrong,
my
prof. looked over it and didn't find anything wrong either, hopefully
you
can.
Thank you in advance.
-helio
---code bellow------
void setup (void)
{
//port/pin setup for the specialCOMM
P3DIR |= BIT4;
P3SEL |= BIT4; // Select pins to alternate function
//clock setup
BCSCTL1 = 0x04;
BCSCTL2 |= 0x88;
//INITIALIZE serial port 0
UCTL0 = CHAR | SWRST; // 8 bit chars - leave in reset mode
UTCTL0 = 0x20; // uclk = smclk
UBR10 = 0x01; // 3.6864MHz/9600bps = 384 = 0x180
UBR00 = 0x80;
UMCTL0 = 0x00;
ME1 |= UTXE0; // Enable Tx0
UCTL0 = CHAR; // 8 bit chars - take out of reset
IE1 |= UTXIE0; //enable Tx0 interrupt
eint();
}
On Mon, 16 Jun 2003 09:39:25 -0300, Pedro Zorzenon Neto wrote:
> Hi helick,
>
> Some radio require CTS/RTS control pins of RS232. Can you send us a
> link to SS900 radio datasheet?
>
> What is the oscilator you are using in MSP430? external cristal?
what
> is the frequency? You could try to lower the baud rate to 300bps just
> for testing purposes.
>
> Hope this helps,
> Pedro
>
> On Sat, Jun 14, 2003 at 05:18:36PM -0400, helick wrote:
>> Hi all,
>>
>> I am having a little problem.
>> I am using my msp430f149 to go out and get some data out of my solar
car
>> and transmit it out using a RF data radio which understands rs232.
>> The program in this message illustrates how I am trying to acomplish
this.
>> I created a dummy char array filled with 'a' chars, then I just try
to
>> send it out. The problem I am having is that the radio does not even
>> twitch. I know they are working because I have connected them to a
couple
>> machines and they talked.
>> I did get the ckt working, so I am pretty sure it's a problem with my
code.
>>
>> Anyways, here is what I am using:
>> - Newlink SS-900 radio (set to 9600bps)
>> - max3233eepp rs232 transceiver
>>
>> I am thinking that maybe I've set my clk/baud incorrectly for
>> 9600bps...
>>
>> I appreciate any help.
>> -helio
>
> --- cut the code ---
>
>
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