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We are currently looking into integrating the EZ-USB FX2LP USB Microcontroller in a new product and we would like to understand better how the smart SIE, which implements the Re-enumeration concept (which we find very appealing), works since we fear its complex hardware implementation might interpret into unreliability, which is essential to the product we develop. If not in any further detail, we would be grateful to at least be informed of whether the smart SIE is implemented using a processor running simple code or rather some intricate hardware.
Expecting your immediate reply.
Solved! Go to Solution.
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Hello,
The Smart SIE feature of the FX2LP is basically used when the bootloader of the device (called Default USB Device) enumerates and allows basic functionality of the device without a firmware running. In this mode, the firmware can be loaded into the RAM over USB while the device is held in Reset. The RENUM bit is set to 0 by the hardware until the download is complete and the device renumerates after which RENUM i set to 1 and the device requests are handled by the running firmware.
Best Regards,
Sananya
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Hello,
The Smart SIE feature of the FX2LP is basically used when the bootloader of the device (called Default USB Device) enumerates and allows basic functionality of the device without a firmware running. In this mode, the firmware can be loaded into the RAM over USB while the device is held in Reset. The RENUM bit is set to 0 by the hardware until the download is complete and the device renumerates after which RENUM i set to 1 and the device requests are handled by the running firmware.
Best Regards,
Sananya
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Thank you for your quick reply.
Unfortunately, we have already figured out this flow of the Re-enumeration process by ourselves by reading the documentation thoroughly. This isn't what we intended by our question. It is essential for us to understand if the functionality of the smart SIE is implemented solely in hardware or by some kind of processor that follows code instructions, which is more reliable in our view.
We did get the impression that it is implemented in code as there are many different and complex features included.
From the document "Getting Started with FX2LP":
"
The SIE translates PHY signals into bytes. All Cypress USB SIEs add logic to handle low-level USB details, such as error correction and Packet ID (PID) synchronization, relieving the programmer of these tasks. This Smart SIE delivers bytes to an endpoint FIFO memory. The Smart SIE also contains logic to enumerate FX2LP as a full-fledged USB device and also capable of loading code into its internal RAM.
"
We do wish to be able to assert it soon so we can continue the development as quickly as possible.
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Hello,
The Smart SIE is implemented in the hardware. It does carry out all the functions mentioned in the App Note but the state machine is designed in the hardware itself.
Best Regards,
Sananya