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Keywords: USB, FAQ, MAX3420E, SPI, Peripheral, Controller.Interface
Aug 17, 2005
APPLICATION NOTE 3597
Frequently Asked Questions About the MAX3420E
Abstract: This application note lists Frequently Asked Questions (FAQs) about the MAX3420E peripheral
controller with SPI interface.
1. General Questions
1. What is the MAX3420E?
2. Does the MAX3420E include a microprocessor?
3. What packages are available for the MAX3420E?
4. Are the MAX3420E packages lead-free?
2. USB Questions
1. What USB speeds does the MAX3420E support?
2. Does the MAX3420E comply with the USB spec? Which revision?
3. How many endpoints does the MAX3420E support?
4. Why doesn't the MAX3420E support isochronous transfers?
5. Can I use the MAX3420E in a self-powered peripheral?
6. Can I use the MAX3420E in a bus-powered peripheral?
7. What external circuitry do I need to connect the MAX3420E to USB?
8. Can you recommend a 3.3V regulator?
9. What does the CONNECT bit do?
3. Interface Questions
1. How does a microprocessor connect to the MAX3420E?
2. You say the SPI interface is 3, 4 or 5 wires. What does this mean?
3. What SPI clocking modes does the MAX3420E support?
4. My CPU uses a 2.5 volt supply, but the MAX3420E uses a 3.3V V
CC
supply. Do I need external
level translators?
5. What is the purpose of the MAX3420E INT pin?
6. Does the MAX3420E support active-low wired-OR interrupts? How about edge active interrupts?
7. How fast can I run the MAX3420E SPI interface (SCLK max frequency)?
8. Is there a low limit to the MAX3420E SCLK frequency?
9. I have an 8-pin microprocessor, and it takes 5 of its' IO pins to connect to the MAX3420E. How
do I do IO?
10. Do I need to add external pullup resistors to the GPIN pins?
11. Can I drive optocouplers from the SPI interface pins?
12. What is the purpose of the VBCOMP pin? Does it power the MAX3420E?
4. Programming Questions
1. How does my firmware talk to the MAX3420E?
2. How do I program the MAX3420E to handle USB enumeration?
3. How do I program a BULK IN transfer?
4. What if a USB IN request comes in while firmware is loading the IN FIFO?
5. How do I know when to load an IN FIFO?
6. What if there is a USB transfer error? Do I need to write code to handle the error condition?
7. How do I program a BULK OUT transfer?
8. How about INTERRUPT transfers?