Flash Magic Forum

In-System Programming Support => LPC9xx/LPC9xxx => Topic started by: Andy Ayre on May 08, 2012, 12:54:15 pm

Title: Electrical Solutions to Programming Problems
Post by: Andy Ayre on May 08, 2012, 12:54:15 pm
The following is from Per Olesen on solutions he found to problems using the MCB900. Thank you to Per for providing this for the benefit of others!

Quote
I use the TSSOP types on my boards, so it is not possible to program them in the MCB900, and then move it to the target board.

In 2 cases I had the problem that it would only program 1. Time.

Solution problem 1: I had a RS485 chip on the RxT TxT line on the target board, and with no external power on the target board, the RxT line was overloaded. I simply put a 100K resistor in serial with the input on the 485 chip, and it worked fine.

Solution problem 2: To be safe I had placed a 100uF capasitor on the VDD of the LPC, and it is too much, it kills the rise time of the VDD from the programmer. 22uF works.