|
| |
This page describes the assembly process for the 912B32 board.
The 912B32 board makes use of several surface mount parts. If you would like to see a
tutorial on soldering surface mount parts, you can check out instructions on Soldering Surface Mount Parts.
Parts List
Your kit should contain the following parts
| Qty |
Value |
Part Names |
| 1 |
6mm |
SW2 |
| 2 |
22pF (220) |
C1,C2 |
| 9 |
.1µF (1206 case) |
C3, C4,C5,C6,C7,C8 (Optional)
C9,C10,C12 |
| 1 |
DB9 Female RA |
SERIAL0 (Optional) |
| 1 |
16mhz |
Q1 |
| 1 |
2x3 Header |
BDM12 |
| 1 |
1M |
R1 |
| 1 |
1N4148 |
D1 |
| 1 |
10k |
RN1 |
| 1 |
10uF |
C11 |
| 1 |
25LC640SN |
IC3 (Optional) |
| 1 |
68HC912B32CFU |
IC1 |
| 1 |
EQ1218 |
SW1 |
| 1 |
KK-02-100 |
VPROG |
| 1 |
KK-03-100 |
POWER |
| 1 |
KK-04-100 |
SCICON (Optional) |
| 1 |
KK-06-100 |
SPICON (Optional) |
| 1 |
MAX3221CAE |
IC4 (Optional) |
| 1 |
MC34064P |
IC2 |
I have marked some parts as Optional. The board will function correctly without these
parts, but certain features may be disabled. There are four groups of optional parts:
 | C4,C5,C6,C7,C8, SERIAL0, IC4 make up the RS232/TTL conversion system. These parts allow
you to connect the 912B32 directly to a serial port on a PC. If you are not interested in
this functionality, you may elect to omit these parts, or to solder them on later. |
| IC3 is a serial EEPROM. If you wish, you may omit this part. |
| SCICON really isn't required, especially if you are planning on using connector SERIAL0
(the DB9 connector). If you decide to omit the RS232/TTL circuit, you can use SCICON in
its place to provide TTL level serial communications. |
| SPICON is also optional. This connects to the SPI port. If you don't plan to use
external SPI devices, you can omit this part. |
When finished, the board will look like:
 
I recommend mounting parts in the following order. This order is basically working from
the center out, so you have the ability to get your solder iron into place.
- The first part to mount is the CPU (IC1). Be sure to note where pin 1 is. The 68HC912B32
has a small indent in one corner that indicates pin 1. The board has a small 1 near pin 1.
It can be seen in the picture below.
- Solder IC1 onto the board. (See Soldering Surface Mount Parts
for instructions).
- Now mount two surface mount capacitors (C3 and C10) on the top side of the board.
- Turn the board over and start working on the back. Time to mount the optional RS232/TTL
level conversion. Because of spacing considerations, I suggest mounting C7 and C8 first,
IC4 second, then C4, C5, and C6. It seems to make mounting a little easier.
- Mount IC3, which is the optional serial EEPROM.
- Mount C9 and C12. That finishes all of the surface mount parts.
- Flip the board over and start with all of the through hole parts. Install C11 making
sure that the polarity of the part is correct. Electrolytic caps have a definite
direction. Most have the '-' terminal marked. The PCB has a mark for the '+' terminal. You
should take care to insure that the '-' terminal of the cap is installed into the '-'
terminal of the board.
- Now install C1, Q1, and C2. These parts don't have a specific direction. You might find
it handy to bend the leads on the backside after you have installed the parts. That will
help hold them in place. Otherwise, you can solder them as you go.
- SW2 is the reset switch, and can be inserted. This part tends to be a little tight to
get into its holes, but once installed it is held in place very well.
- Install IC2 so the flat side aligns with the flat side on the silk screen. Note that the
lead spacing on IC2 is fairly small. You should take care not to create a solder bridge
when soldering this part.
- Install R1. Polarity doesn't matter.
- Install D1. The polarity of this diode is important. The diode should have a black band
on one edge. This should be aligned with the band as shown on the silk screen.
- The resistor network RN1 is a 10k isolated network. Polarity usually doesn't matter, but
pin 1 is usually marked with some sort of dot. Pin 1 on the board is clearly marked.
- You should now flip the board over and solder the through hold parts. Then, trim the
leads.
- Next we will install the connectors. Mount the 2x3 BDM12 connector and the 3-pin POWER
and 2 pin VPROG connectors.
- If desired, mount SCICON as the 4 pin connector
- If desired, mount SPICON as the 6 pin connector.
- Mount the switch SW1
- The last connector in the kit is SERIAL0. This part is mounted by inserting the PCB
between the solder cups, as seen in the overview picture above.
Congratulations, you have finished assembling your 912B32 board!
|
