Products > Test Equipment
Siglent SDS1104X-E and SDS1204X-E: Bode plot with a non-Siglent AWG
UniSoft:
--- Quote from: Roman oh on May 31, 2021, 02:16:07 pm ---But the 6900 does not respond to the message stream when it's connected to the Rx pin on the 8 pin connector on the back panel.
The circuit diagram appears to show a CH340G with its RxD and TxD lines simply wire-OR'ed with the back panel connections (using limiting resistors) but does not show any connection between this circuit element and the FY6900's "processor" FPGA. Since the USB is working, I guess the CH340 is OK, and beyond that it's just a couple of resistors.
--- End quote ---
I had the similar problem...
RxD and TxD goes to MCU (4pin cable)
Now they use CH340N >:(, it looks like this shit IC makes LOW level (i.e. ground) on signal pins (when USB not connected)...
so you just simple get resistor divider by 2!!!
So instead of 3.3V signals there was less than 1.6V, what was not enough for MCU and therefore it not respond.
Roman oh:
Thanks, unisoft. I didn’t get that the MCU was actually on the front panel pcb. That helps a lot. I know what to do now, I think. Did you find a fix?
UniSoft:
--- Quote from: Roman oh on June 01, 2021, 12:26:38 am ---Did you find a fix?
--- End quote ---
I just reduced the resistance of the resistors coming from the TTL connector ...
Roman oh:
Yes, it’s clearly a (nother!) design fault. They have a 2K2 resistor at R20 (unnecessarily) isolating the CH340 Tx pin instead of at R19 isolating the Rx pin, so the input on the TTL connector sees a 300 ohm to 300 ohm divider, instead of a 300 into 2200, which would have worked. The simplest “fix” would be to swap R19 and R20. However, their design also feeds nominal 5V to the 3.3v MCU and appears to rely on the resistors to limit the current into the MCU pin. The MCU has had its ID ground off, so I can’t know whether the inputs are 5V tolerant; the voltage at the pin is about 3.9v which is one diode drop above the 3.3V rail. Don’t know if this is good or bad.
I went a bit more complex and made up a simple 4-transistor 3-input gate/level-shifter (I want a 3rd input because I envisage putting the 8266 inside the box, and may want to also “play” with the TTL inputs some time.
All working now.
Geeboh:
Hi guys, After following this thread including Mr. tick's esp01 bode plot github code.
Problem :
When trying to hook up my 1104x-e to fy6900 via ESP01s, my scope will gone completely freeze while attempt connect with the ESP01 and in the same time the ESP01 also will restart in this process.
Until now i try so many things get it work even personally pm mr tick through youtube and yet seems that i cant find the solution.
Anyone here can guide me on how to connect esp01 with 1104x-e.
Thank you in advance
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