to check bootloader, best if you have the 900c compatible serial cable, you simply plug it in the
(proprietary but pinout is known!
) serial port on 900c, and connect it to your PC, then in any terminal program select 115kbps and software xon/xoff flow control. no parity, 8 bits and stop bits 1. at this point 900c should have no power attached whatsoever
(no AC, no batteries
). now, plug AC in and watch the terminal. do you see anything? the bootloader should be announcing itself as bsquare bootloader for MP900 or similar and some other debug info should be scrolling on screen until the 900c goes to sleep
(if you don't press power button, it will go to sleep after a while
).
if you see nothing or only see a couple of lines before it stops, then maybe it got corrupt. see jtag description at:
http://hpcmonex.net/nec900/files/jtagging.html
jtag can also be used to test whether the board can power on at all with a *functional* CPU
(if it can, you should get cpu recognized in jtagtools
), especially if you have no serial cable for testing.
the bad power button is also a reality, one of my devices is waiting for repair. via serial cable i can see bootloader going to sleep even when pressing power on key.
(entire keyboard connector is broken, will have to replace that
)
finally a simple way of testing: put in a fully charged main battery
(no AC
), and leave it there for half a day, then see if charge level dropped significantly. if yes, then board was able to power on but perhaps cpu crashed on ccorrupt bootloader code and so hardware could not be configured to go to sleep properly hence eating up the battery in a few hours.
Edited by cmonex 2009-03-08 8:04 PM
