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Terminology and tips
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USB FX2 microcontroller stall term/definition is used to describe the situation where your TE USB FX2 module's FPGA works normally (you are still able to connect to FPGA using JTAG connection) but you are unable to connect to it via USB connection despite having the correct USB drivers installed. TE USB FX2 modules are industrial products and if wrong firmware is written in EEPROM (=> USB unresponsive but FPGA's working) it can easily corrected (without using JTAG connection) with EEPROM switch and USB connection: the solution is quite easy and fast (5-10 seconds) under Windows (implicit two-step recovery boot) and it is also possible under Linux (explicit two steps -step recovery boot). |
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If the user is unsure about the suitability of a new firmware (wherever it is the source), it's a good idea to load it into RAM first to make sure it is not totally broken. A reference firmware (from Trenz Electronic GitHub) is suitalble and tested; it can be used to test the functionality of TE USB FX2 module and SW APIs. The only possible problem with reference firmware files is the corruption of the downloaded .iic file. If the user have problem with reference .iic file should consider to check the integrity of the file and/or download a new copy of desired .iic file from Trenz Electronic GitHub. |
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Writing wrong (or corrupted) firmware to EEPROM will bring the USB FX2 microcontroller to stall. To bring it back out of a stall, the firmware recovery procedure differs upon the host operating system:
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Recovery Boot
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To default, the FX2LP FX2 hardware (i.e with EEPROM isolated =>hardware's first stage loader) enumerates the USB FX2LP FX2 microcontroller chip as VID=0x04B4 (Cypress) and PID=0x8613 (FX2LP), and provides support for loading firmware into RAM. To default, using the FX2LP FX2 hardware (i.e with EEPROM isolated => hardware's first stage loader ) it is possible to write a new firmware in RAM but not in EEPROM. |
The USB FX2LP FX2 microcontroller hardware's first stage loader (supporting the 0xA0 vendor request) can't write into external memory (EEPROM for example).
Configurations that put firmware into external memory thus need a second stage loader. For typical "flat" memory architectures, a loader supporting the 0xA3 vendor request is used to write into that memory. Similarly, a second stage loader that supports the 0xA2 or 0xA9 vendor request is needed when writing boot firmware into an I2C EEPROM. These 0xA2, 0xA9 and 0xA3 vendor commands are conventions defined by Cypress.
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Implicit Two-Step Recovery boot ≈ Explicit Two-Step Recovery Boot
It is possible to write in EEPROM only using a 2nd stage loader firmware supporting EEPROM programming (aka intermediate good firmware) running in RAM; normally the bootloader Vend_Ax.hex is used.
- In the case of
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- (at this time, only Windows) the 2nd stage (boot)loader firmware is loaded without the explicit intervention of the user.
- In the case of
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- (mainly Linux) the 2nd stage (boot)loader firmware is loaded with the explicit intervention of the user.
Both recovery boots use exactly the same procedure (under the hood, they are one and the same), but in Windows OS case the 2nd stage (boot)loader firmware step is
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hidden/implicit in loadEEPROM() function used by
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(IMPLICIT two step) Recovery Boot
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The 2nd stage loader firmware is loaded automatically without the explicit intervention of the user. At this time, it is only possible with Windows OS |
In a recovery boot (see here) the user should (the necessary device driver is assumed already installed)
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CyConsole
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The CyConsole's Lg EEPROM button, CyControl's EEPROM button and OpenFutNet's IIC button call the loadEEPROM() function. This function is used to program 64-Kbyte EEPROMs. When the button (CyConsole's Lg EEPROM button, CyControl's EEPROM button or OpenFutNet's IIC button) is clicked, the user is prompted to select a (.iic) file to load into the EEPROM. This button first downloads the Vend_Ax(_Fx2).bix file, then sends the 0xA9 vendor request to program the EEPROM. |
The CyConsole/CyControl/OpenFutNet program will load
(HIDDEN STEP 1) an intermediate good firmware supporting EEPROM programming (normally the 2nd stage bootloader Vend_Ax.hex ) in RAM;
- (EXPLICIT STEP 2) the desired good firmware into FX2 microcontroller's external EEPROM using the the intermediate good firmware (2nd stage bootloader Vend_Ax.hex) in RAM.
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then sends the 0xA2 vendor request to program the EEPROM. THIS BUTTON SHOULD NOT BE USED.
(EXPLICIT Two Steps) Recovery Boot
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| Explicit two steps recovery boot could be carried out with both Windows and Linux OSes. |
In a two step recovery boot, the user should (the necessary device driver is assumed already installed):
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CyControl
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and
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OpenFutNet
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A single command line recovery boot could be carried in Linux OS using fxload (with -c and -s "loader" option on the same command line, where loader is Vend_Ax.hex).
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| title | fxload and Linux distribution |
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fxload is already distributed with some Linux distribution.
Unfortunately, the fxload of this distribution does not normally include a good second-stage boot loader for all vendor specific commands 0xAx and hence cannot directly be used to program EEPROM storage. However, such a bootloader is available separately if you dig around on the Cypress page; it is Vend_Ax.hex but it should be manually retrieved/downloaded. (Note: This "second stage bootloader" is sometimes also called "third stage").
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