Hardware Hacking Projects for Geeks

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Part I: Basic Hacks, Tools, and Techniques

Place R4 (labeled 104, 10 + 4 zeros = 100K), using the same technique as

in previous steps.

Next, test your work so far.

Solder a 30-gauge wire to pads 19 and 20 of the edge connector. Use anoth-

er short wire to temporarily connect both of these wires to ground. Plug in

the data cable if it’s not already there.

Power up the board as you did in the first test. Move the wire on pad 19 to

the +5V test point 1 (a small lead from the TP location). Use a large 100K-

leaded resistor (not included with kit) between pad 19 and +5v. Use some

sticky tape to hold the board and the growing number of test leads and

wires, as shown in Figure 5-24.

The MCU (microcontroller unit) should be in program mode and now out

of reset.

Run the ICP (in-circuit programming) program from either Temic or

Philips, depending on which part you have. Be sure that no other program

has the COM port already open (for example, your Palm’s Hot Sync). Select

the CPU and 20 MHz clock from the onscreen menus in the software.

Do a “blank check” on the part using the ICP software. If the program

comes back with “part blank” or “part is not blank,” all is well. If you get

“part must be reset” or “invalid response to U,” then double-check the

oscillator and solder connections, and look for shorts on the board due to

solder blobs or misal ...