content/eip545b_firmware.rst@edef9b48311f
content/eip545b_firmware.rst
Thu, 10 Nov 2022 15:31:51 +0100
- author
- David Douard <david.douard@sdf3.org>
- date
- Thu, 10 Nov 2022 15:31:51 +0100
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========================================== EIP 545B RF Frequency Counter - Firmware ========================================== :author: David Douard :Category: Electronics :Tags: test equipment, RF, EIP, 545, 545A, 545B, 575A, 578A, counter :series: EIP545B Frequency Counter :series_index: 7 This part will focus on the analyze of the firmware I made so far, in order to fix a few issues I have encountered in my unit, as related in previous `previous part <{filename}/eip545b.rst>`_. **It will be updated** as I make progress on disassembling and understanding the firmware. Original Firmware ================= The original firmware I have in my unit if the version "2060048 SPECIAL WB68". Here are the 3 EPROM images dumped form there: - U11 `EIP545B-2060048-02B <{static}/data/eip545b/EIP545B-2060048-02B_SPECIAL-WB68.bin>`_ - U12 `EIP545B-2060048-03B <{static}/data/eip545b/EIP545B-2060048-03B_SPECIAL-WB68.bin>`_ - U13 `EIP545B-2060048-04B <{static}/data/eip545b/EIP545B-2060048-04B_SPECIAL-WB68.bin>`_ Modified Firmware ================= The current version of the firmware I run on my device is the following: - U11 `EIP545B-2060048-02B-mod <{static}/data/eip545b/EIP545B-2060048-02B_SPECIAL-WB68-modified.bin>`_ - U12 `EIP545B-2060048-03B-mod <{static}/data/eip545b/EIP545B-2060048-03B_SPECIAL-WB68-modified.bin>`_ - U13 `EIP545B-2060048-04B-mod <{static}/data/eip545b/EIP545B-2060048-04B_SPECIAL-WB68-modified.bin>`_ I have fixed a few issues of the original firmware, but not all of them: - the power meter works (with a very quick calibration for now), - there is no more a 160MHz Offset on startup, but the Offset lights remains on (until I manually clear the frenauency offset values), - the 5 digits displayed on startup is not fixed either. Disassembling the firmware ========================== f9dasm ------ At first, I used to use `f9dasm <https://github.com/Arakula/f9dasm>`_ to disassemble the firmware. It does the job but seriously lacks power. Nonetheless, here is the result of this first attempt: `EIP545B-2060048.f9dasm <{static}/data/eip545b/EIP545B-2060048.f9dasm>`_ In this file, I only identified a bunch of routines. The interesting part starts at address 0x5F19, which is the address where the CPU jumps after a RESET (as configured in the interrupt vector table at the very end of the address space, namely addresses [0xFFF2:0xFFFF]. radare2 ------- Then I discovered `radare2 <https://www.radare.org>`_, which is an awesome tool. When I started to try to use it, it had no complete and proper support for the MC6809 back then, so I had to write my own version of the architecture support, including ESIL support (unfortunately I never took the time to finish the work and submit my work upstream. I may try to finish this in the next few month).
