Console with One-Wire Temperature on MSP430F5529 LP

[zeke 693]

Hi Guys,

 

This has been on my bucket list for a while.

 

I've put together a CCS6 project that gives the user a serial console to the MSP430 with the ability to read a DS18B20 sensor by issuing a serial command.

 

Here's a copy-paste of some of my interactions on the console:

*************************************************************************************
* CommandConsole Ver:0.1 Released by:RandomElectrons.com Built:Sep 22 2014 16:33:28 *
*************************************************************************************
h
*******************************************************************************
B,b: Banner command
C,c: Clear screen command
H,h: Help command
M,m: Memory command
R,r: Reset command
S,s: Sensitivity command
T,t: Temperature command
V,v: Version command
*******************************************************************************
OK
t?
T=254 raw decimal counts
T=15.87'C
OK
t?
T=213 raw decimal counts
T=-13.31'C
OK
T?
T=29 raw decimal counts
T=-1.81'C
OK
T?
T=9 raw decimal counts
T=-0.56'C
OK
T?
T=6 raw decimal counts
T=0.37'C
OK
T?
T=242 raw decimal counts
T=15.12'C
OK
B?
T=440 raw decimal counts
T=27.50'C
OK

I have also uploaded my CCS6 project as a zip file.

 

As the pictures suggest, I have created this on an F5529 LaunchPad board.

 

The DS18B20 is wired up in 3-Wire mode and is connected to P1.4 of the LP and read with the typical bit-banging method. 

 

I have wired in an adafruit ftdi friend onto P3.3 and P3.4 for USART to the PC operation.

 

I use the Terminal inside of CCS6 to interact with the system.

-->View-->Other-->Terminal-->OK

 

The console portion of this project was inspired by and adapted from http://www.adnbr.co.uk/articles/parsing-simple-usart-commands

 

Comments are welcomed.

 

RE_OneWireOnF5529LP.zip

[bluehash 1,581]

Thanks for sharing @@zeke.

[acesh 0]

I am using baud rate 115200 but I am getting different characters. The code seems to be working, I can read the temperature values but I am not getting correct characters in the COM port. What might I be doing wrong?

[zeke 693]

@@acesh

 

Have you made any alterations to the original code?

 

Make sure to set your serial port to 115200, 8N1.

 

Can you show us what you see?   Please copy-paste your console output here.

[acesh 0]

I can see:

#Q

[zeke 693]

@@acesh, 

 

There's something not quite right with the communication parameters. 

 

If the communication parameters are truely 115200,8N1 then try changing the encoding to ASCII.

[acesh 0]

The encoding options are ISO-8859-1, UTF-8 and Cp1252. What should I use? Can you walk me through the connection of the FTDI Friend?

 

Thanks

[veryalive 49]

Hi guys.

I used Zeke's sw a long time ago, so maybe my recollection is correct / useful:

.... Check your bit times with a scope ....?

 

I recall changing baud rate down to 9600 and also got bit errors.

The logic analyser showed faster bit times than 104 uSec (9600), it was around 95 or 97 ?

When I adjusted dividers in the async uart setup routine, it worked.

Maybe this helps?

Cheers....

[oPossum 1,083]

This is obviously wrong:

 

 UCSCTL2 |= 499;                           // Set DCO Multiplier for 16MHz
                                            // (N + 1) * FLLRef = Fdco
                                            // (499 + 1) * 32768 = 16MHz

change to...

 

 UCSCTL2 |= 499;                           // Set DCO Multiplier for 16MHz
                                            // (N + 1) * FLLRef = Fdco
                                            // (499 + 1) * 32768 = 16.384 MHz

and also change...

 

 const unsigned long smclk_freq = 16384000UL; // SMCLK frequency in hertz

and delete (or fix and make use of)...

 

/*******************************************************************************
 *
 ******************************************************************************/
#define F_CPU 16000000UL
#define BAUD 19200
#define BAUD_PRESCALE (((F_CPU / (BAUD * 16UL))) - 1)