Niranjana Murthy

External bus interface and Pierce oscillator

Discussion created by Niranjana Murthy on Apr 26, 2006
Latest reply on Apr 28, 2006 by Alban Rampon
Hi, i'm using 16 bit microcontroller MC9S12XDT512CAG in normal expanded mode and i selected 25MHz as crystal frequency. I tied the XCLKS\ pin low configured to full swing pierce cyrstal oscillator(0.5 to 40MHz range).  I'm interfacing 3.3V lan device with 5V tolerant input to MC through External Bus Interface (PORTS A, B, C, D and E).
 
1. would this 25 MHz pierce oscillator would works in this configuration.
 
2.  please can any body tell me what is FULL SWING pierce crystal oscillator. and can suggest any manufacturer..?
 
3. I didn't able find the relation between external bus frequency, system clock frequency. In this case what is the bus frequency?
 
4. Datasheet MC9S12XDP512V2.pdf page-837 signifies, by setting the ITHRS bit of EBICTL0 register we can configure the EBI to communicate with 3.3V devices with 5v tolerant inputs. But i'm not find the REDUCED INPUT THRESHOULD VOLTAGE LEVELS???? Please any body inform me regarding this.
 
Please any body help me.......
 
Awaiting for ur reply.
Ebda

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