3c3f3c4247
Build requires SDCC, the Small Device C Compiler.
35 lines
1.9 KiB
Plaintext
35 lines
1.9 KiB
Plaintext
This is the OpenULINK firmware for the Keil ULINK JTAG adapter.
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The main components of the Keil ULINK adapter are:
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- Cypress EZ-USB microcontroller: enhanced 8051 CPU + USB core (1.1 Full-Speed)
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- SRAM memory chip
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- Level shifters to support different JTAG signal voltage levels
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- Pin headers for various JTAG pin assignments
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This firmware can only be run on the ORIGINAL Keil ULINK adapter, not on the
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newer ULINK2, ULINK-ME or ULINK-PRO, as these adapters are based on different
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hardware.
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To compile the firmware, the SDCC compiler package is required. Most Linux
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distributions include SDCC in their official package repositories. The SDCC
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source code can be found at http://sdcc.sourceforge.net/
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Simply type "make hex" in the OpenULINK directory to compile the firmware.
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"make clean" will remove all generated files except the Intel HEX file required
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for downloading the firmware to the ULINK adapter.
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Note that the EZ-USB microcontroller does not have on-chip flash, nor does the
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Keil ULINK include on-board memory to store the firmware program of the EZ-USB.
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Instead, upon initial connection of the ULINK adapter to the host PC via USB,
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the EZ-USB core has enough intelligence to act as a stand-alone USB device,
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responding to USB control requests and allowing firmware download via a special
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VENDOR-type control request. Then, the EZ-USB microcontroller simulates a
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disconnect and re-connect to the USB bus. It may take up to two seconds for the
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host to recognize the newly connected device before OpenOCD can proceed to
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execute JTAG commands. This delay is only visible when OpenOCD first uses a
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blank (unconfigured) ULINK device.
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Once the user disconnects the ULINK adapter, all its memory contents are lost
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and the firmware download process has to be executed again. This also maintains
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compatibility with the original Keil uVision IDE, which will happily download
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its own firmware image to a blank ULINK adapter.
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