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Discussion Groups | LPC900 | Re: LPC936 with external crystal
Find help, specifications and source code for the LPC900. The LPC900 challenges Microchip and AVR based on the worlds most popular 8-bit architecture the 80C51. With a 2-clock core the LPC900 series is a high performance, very flexible and low cost 8-bit microcontroller family. Designers using or interested in these devices are encouraged to share their know-how and ask questions.
Re: LPC936 with external crystal - Alvin Schmitt - Jul 8 5:59:48 2008
Try a solid state relay that switches at the zero voltage crossover point. I made my own
and it stopped noise getting from the relay (mechanical) to the controller circuit.
Snubber circuit also helped as part of my homemade solid state relay. Alvin....
"vijay.satra" wrote: i want accurate timing so i used external
crystal of 8MHZ with
LPC936 but i found the following problems.
1.With crystal (8MHZ) & its capacitor value 33pf or 22pf the LPC936,
the unit gets hang while contactor switching or any kind of noise
occurs at supply terminals.
2.The unit works ok after the capacitor is removed but some time
controller does not startup properly.
3.The unit works fine if internal on-chip oscillator is used.
Configuration byte
P0M1 = 0xf4;
P0M2 = 0xb;
P1M1 = 0x2e;
P1M2 = 0x9e;
P2M1 = 0;
P2M2 = 0x81;
DIVM = 0x1;
TRIM &= ~0x40;
AUXR1 |= 0x80;
Kindly suggest some method to solve the problem.
APSTRON
P.O. Box 10336
Blacksburg VA 24060-1442
www.blacksburg.net/~schmitta
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )
"vijay.satra"
LPC936 but i found the following problems.
1.With crystal (8MHZ) & its capacitor value 33pf or 22pf the LPC936,
the unit gets hang while contactor switching or any kind of noise
occurs at supply terminals.
2.The unit works ok after the capacitor is removed but some time
controller does not startup properly.
3.The unit works fine if internal on-chip oscillator is used.
Configuration byte
P0M1 = 0xf4;
P0M2 = 0xb;
P1M1 = 0x2e;
P1M2 = 0x9e;
P2M1 = 0;
P2M2 = 0x81;
DIVM = 0x1;
TRIM &= ~0x40;
AUXR1 |= 0x80;
Kindly suggest some method to solve the problem.
APSTRON
P.O. Box 10336
Blacksburg VA 24060-1442
www.blacksburg.net/~schmitta
(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )