Main Board Bug Fixes

Version 1.0
12 April 01

*** Must decide on placing R12, R14, R16, R21

1. Place U11 MAX1626 on board

1a. Replace R31 (0.2 ohm) with 0.1 ohm 1206 resistor

2. Powerup check with 7.2V on current limit to check board operation
check
- no current consumption while not powered.
- power supplies come up to 3.3V and 5V respecitvely (indicated by LEDs)
- check ripple on 3.3V line (<100mVp-p)
- check current consumption (instantaneous kick of around 400mA but typically down to 100mA or less)
- crystal oscillation (7.3728MHz) and clock out (3.0..MHz by default 1/2 oscillator)

3. Cut pin 6 from JTAGCON

4. LED operation/CPU stability
- do basic Emulator check and load ledtest.out to test a flashing LED

5. Change tie to 3.3V on R28 (leads to Q1) to pull to reset line:
cut R28 connection to 3.3V via. Put wire wrap connection on bottom side to pin 5 of U19.

2. Swap pin 2 and pin 2 on top and bottom matching ICL7667 pins. So:
U7(2)  PWM2  <-> U8(2)  PWM4
U12(2) PWM6  <-> U13(2) PWM8
U14(2) PWM10 <-> U20(2) PWM12

I did this on the start board  as:
U7 , bottom, 		- cut track from R43 to CPU near R43
U12, bottom,		- remove R47 and replace with 10K to U12(2)
U14, bottom,		- cut track from R51 between via and R51

U7 , bottom, 		- place wire wrap on U7(2) thru via near C25 onto cleared R45 pad
U12, bottom,		- place wire wrap from via connecting U13(2) to U12(2) on resistor leg
U14, bottom,		- place wirewrap from via connecting U14(2) onto U14(2) leg

U8, top			- remove R45 and replace with 10K to U8(2)
U13, top		- cut track between via and R49 near via
U14, top		- cut track midway between R53 and via

U8, top			- place wire wrap on U8(2) from via near R44 from U7(2)
U13, top		- place wire wrap on U13(2) thru via near C26 (2nd one away) onto R47 removed pad
U14, top		- place wire wrap on U14(2) from via 

- test with motor driver test code mtest.out
- should see ramping dead-band PWM waveforms on each channel individually

2. Place KCon, KPWR, MTRCON1, MTRCON2, MTRCON3