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Maxim > App Notes > INTERFACE CIRCUITS
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
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9. How do I program a SETUP transfer? 10. Do I need to program the USB data toggles? 11. The MAX3420E interrupt request bits are cleared by writing "1" to them. Is this backwards? 12. Do you have any programming tips? 5. Host Software Questions 1. How does my Windows application talk to the MAX3420E? 2. Does Maxim supply a custom Windows driver? 3. What example code does Maxim supply? 4. I want to design a MAX3420E-based device that does not conform to a standard Windows class.
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speed). Most applications that seem to require ISOCHRONOUS bandwidth can actually be handled with BULK or INTERRUPT transfers. This is because most of the ISOCHRONOUS bandwidth available to a USB device in a system is also typically available for BULK/INT transfers. 5. Can I use the MAX3420E in a self-powered peripheral? Absolutely. In fact, the MAX3420E has features specifically intended to support self-powered applications. For example, in a self-powered application the peripheral ne
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By setting a control bit (FDUPSPI, full-duplex SPI), the MOSI and MISO data appear on separate pins, providing a 4-wire interface. Finally, an INT (interrupt out) pin can be connected to a processor's interrupt system. 3. What SPI clocking modes does the MAX3420E support? The SPI mode is usually expressed in the form (x,y) where one variable is the clock polarity, CPOL, and the other is the clock phase, CPHA. The MAX3420E operates in modes (0,0) or (1,1) without requiring a mode bit. Th
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isolating USB. 12. What is the purpose of the VBCOMP pin? Does it power the MAX3420E? No. The VBCOMP pin does not power anything in the MAX3420E. It goes only to an internal comparator to detect the presence of V . BUS 4. Programming Questions 1. How does my firmware talk to the MAX3420E? The MAX3420E has a set of 21 registers that are accessed by its slave SPI interface. The SPI master first sends a command byte that sets the register address and direction, and then transfers one or
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9. How do I program a SETUP transfer? The USB host uses a CONTROL transfer to send a SETUP packet to the MAX3420E along with eight bytes that serve as a USB "op-code". The MAX3420E stores these bytes in an 8-byte FIFO, and then asserts a Setup Data Available interrupt request. The SPI master responds by reading the eight SETUP bytes at register address R4 (SUDFIFO), interpreting the USB request from these bytes, and taking the appropriate action. When finished servicing the request, the
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■ Purchase a general-purpose driver. These typically consist of the USB driver and a companion library of C functions to access the driver. Drivers are matched to the VID (Vendor ID) and PID (Product ID) in your device descriptor. Microsoft has announced a general-purpose BULK driver for USB in the upcoming "Vista" version of Windows. 5. How does the MAX3420E compare with USB 'serial bridge' chips? USB serial bridge chips connect to a PC using its USB port, but appear as a virtual COM
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More Information For technical questions and support: http://www.maxim-ic.com/support For samples: http://www.maxim-ic.com/samples Other questions and comments: http://www.maxim-ic.com/contact Related Parts QuickView -- Full (PDF) Data Sheet -- Free Samples MAX3420E: AN3597, AN 3597, APP3597, Appnote3597, Appnote 3597 Copyright © by Maxim Integrated Products Additional legal notices: http://www.maxim-ic.com/legal
