a person from Germany asked me if there is a chance to request from HanTekway to remove the automatic
20MHz lowpass filter. Well, maybe they will do it some day, but for now i have DIY solution.
You don't know what i'm talking about? Probably you do. Each time while changing volt/DIV from 5mV/DIV
to 2mV/DIV the firmware is automatically enabling the 20MHz lowpass. While this is only pissing me off
a bit there is another example which really sucks. When you set to 2mV/DIV and disable the 20MHz lowpass
you can't then change anything in Acquire menu (e.g. sampling type from normal to avg, or even
not the memory depth) without having the 20MHz lowpass activated again.
I've attached patched dso.exe (firmware 2.06.3_121027.0), to install it just copy it over uart to DSO and reboot.
If you don't have uart connected or linked use the tool from Peter
http://www.dreisiebner.at/dso-usb-tool/ to copy it from e.g. usb flash drive to DSO, e.g.
cp /mnt/dso_update.exe /
After the reboot the startup script will move the dso_update.exe to dso.exe and your DSO will
startup with patched version (it will display 2.06.3_121027.
1 )
For those of you who wish to learn what i did in the firmware (
note: this is fw for 2.06.3_121027.0).
- to disable 20MHz lowpass while changing Volt/DIV from 5mV to 2mV/DIV
In the firmware there is function "DoCoastCountVoltBase" (hex address 0x3BE88), which
contains two jumps to another one function - this is what i changed from "BL BwLimitWhenVbChange"
to "NOP". The first address to patch is 0x3C008, the 1C FD FF EB need to be repalced by 00 00 A0 E1.
The second address is 0x3C098, here the F8 FC FF EB must be repalced by 00 00 A0 E1.
- to disable 20MHz while operating in Acquire menu
In the firmware there is function "InitLcdUnwaveareaShow" (hex address 0x2E34C), which
contains two jumps to 2 other functions. The first change is from "BL SetBwLimitVal" to "NOP",
the second is "BL BwLimitWhenVbChange" to "NOP". The first address to patch is 0x2E52C,
the A8 12 00 EB need to be repalced by 00 00 A0 E1. The second address is 0x2E534, here
the D1 33 00 EB must be repalced by 00 00 A0 E1.
As said above, these changes are for current fw 2.06.3_121027.0, for other versions you will
have to disassemble both (this and target fw), compare the affected functions to find out the
new address and the patch it away.
EDIT: Btw, there is another one situation where the fw is auto enabling the 20MHz lowpass,
when you se both channels to 2mV/DIV and change to XY from YT. In my opinion this is ok,
i don't see a reason to have lowpass disabled here - but if you don' t like it, well patch it away.