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T-238+ Assembly Manual 

Rev. 3 March 2006 

Page 7 of 11 

Almost done with the main board 

At this point, these should be the only items left in the 
main board kit: 
 

NOTE:

 Keep U3 and U4 in the antistatic foam 

 
[  ] U3 MC68HC908GP32  
[  ] U4 MAX23 
 
[  ] 2.1 mm Coaxial Plug  
 

Board Check 

You are now complete with the soldering of the main 
board.  Other than the two ICs mentioned, the only 
component locations that should not hav e anything loaded 
are P2 and P3.  These are for debug and program 
dev elopment use and should not normally be needed. 
 
DS1 may or may not be loaded depending on where you 
want your activ ity LED to be.

Содержание T-238+

Страница 1: ...pose Motorola MC68HC908GP32 microcontroller based board intended for use with the Dallas Semiconductor 1 Wire bus and any device that needs a serial connection Four push button switches and a Liquid Crystal Display LCD module provide the user interface The initial application for the T 238 is a controller that accepts data from a Dallas Semiconductor weather sensor unit processes it and formats it...

Страница 2: ... red gold R1 4 10K brown black orange gold R2 3 8 18 1 20K red black orange gold R20 Resistor 1 2 w 5 Carbon Film 1 4 7 yellow violet gold R5 Resistor Pack 5 Carbon Film 1 10K R19 Resistor Trimpot 1 10K Trimpot 103 V1 Capacitors Capacitors may be marked in various ways The typical markings are listed but may vary Find all that match and the remaining ones if any should become apparent by eliminati...

Страница 3: ...tive foam and the PCB first Always touch and hold the foam first before touching the IC Always touch and hold the printed circuit board before inserting the IC into its socket Never leave the ICs on anything but the foam or the PCB Construction Refer to the layout diagram for clarification of parts placement All references to up down left and right assume that you are looking at the PCB side with ...

Страница 4: ... and double check for a bent pin CAUTION Take care to avoid solder bridges Install the following IC sockets Align the notch in the socket to the notch in the silkscreen outline U1 16 pin U2 40 pin Now check your work All leads should be soldered There should be no solder bridges a blob of solder that shorts two adjacent soldered connections or cold gray and or grainy looking solder connections OK ...

Страница 5: ... one pin Check for proper alignment If alignment is off you can reheat the one pin to adjust Once the alignment is correct solder the rest of the pins and then reflow reheat the first pin you soldered NOTE It is important to ensure these headers are installed flush so they come out of the board vertically This is especially important for J3 the modem header J2 2x5 male header DO NOT INSTALL J1 YET...

Страница 6: ...pin male header to the back of the LCD module During this time you need to protect the LCD screen from splatter while soldering Ensure the LCD screen is protected Loosely insert the 16 pin male header into the female header just to the point where there is some resistance to the insertion Install the four 1 2 spacers on the back of the LCD module Install them by screwing in the 3 8 spacers into th...

Страница 7: ...foam U3 MC68HC908GP32 U4 MAX23 2 1 mm Coaxial Plug Board Check You are now complete with the soldering of the main board Other than the two ICs mentioned the only component locations that should not have anything loaded are P2 and P3 These are for debug and program development use and should not normally be needed DS1 may or may not be loaded depending on where you want your activity LED to be ...

Страница 8: ...shorter lead identifies the cathode lead Insert the LED according to the silk screen outline the flat side or short lead to the flat side of the silkscreen NOTE Mounting the LED on this board assumes you did not mount it on the main board DS1 Red LED if you want it here Solder and clip the leads 2 total Male Header The male header will be installed next The plastic body of the part should rest flu...

Страница 9: ... T238 Observe anything unusual such as components heating up smoke or smell Remove power immediately if anything unusual appears Place the ground lead of your voltmeter on the center pin of U3 This will be the ground reference for the rest of the measurements Measure the voltage on the voltage regulator U3 on the pin closest to the edge of the board It should be between 8 and 14V If it is 0V then ...

Страница 10: ...as described above LED flashing approximately once per second Remove power then insert U1 slowly Observe that all the pins slide into the socket Watch for pins that bend under the IC or out of the IC socket Insert U1 MAX232 With the ground lead of your voltmeter on pin 15 of U1 check the following voltages Check Pin Voltage Remedy U1 Pin 16 5 Check IC socket U1 Pin 2 Greater than 8V Check IC socke...

Страница 11: ...f for example red is on the left in both connectors then this cable does not reverse the signal wires When the weather sensor is connected properly the LCD will not give any bus error messages It will complain that it has no IDs and will ask that your run setup This is perfectly normal No bus error messages at all when powering up the weather station Congratulations You have completed the power up...

Страница 12: ...odem Board 3 8 Standoff 4 1 2 Spacer 4 1 2 Standoff 2 Chassis Screws 4 Board Screws 2 Board Screws 2 Spacers Screws and Inter board Connectors view from top 16x1 Male 16x1 Female 2x8 Female 2x8 Male Component side of T238 Main board Solder side of T238 Main board Regulator Heatsink Heatsink Assembly ...

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