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Dear members,
We need to be able to have three different ways for burning the firmware into the micro.
1- Emulator
2- RS232 driver User MODBUS
3- RS232 driver from our cloud
each of these ways has its own assigned pins in micro. I want to find a kind of chip that let me choose (or switch) between different pins while burning the firmware. In RUN MODE the connections are like:
RUN MODE MD=1
BOOT MODE MD=0 using USER MODBUS
BOOT MODE MD=0 using USER CLOUD
any suggestion would be appreciated.
Farzaneh
When looking at the left side, the EMULATOR TDx signals just need to be disconnected; use 1:1 switches like the SN74LVC2G66.
For the RS232 USER and CLOUD signals, use 2:1 switches like the TS5A23157 or TMUX1574.
Alternatively, when looking at the right side, for the MICRO TDx signals, you can use 3:1 multiplexers like the TS5A3357 or TS5A3359. But a two-channel 4:1 device like the TMUX1309 is cheaper.
The MICRO SCIxx signals just need to be disconnected; use 1:1 switches like the SN74LVC2G66 or SN74LV4066A.
Better recommendations might be possible if we know the voltages and frequencies.
Hey Farzaneh,
I think Clemens solutions are good! I took a look before seeing his solution and came up with same feedback as his second "Alternatively" plan. TMUX1309 would be a good cheap option and really any 1:1 switch for connnecting and disconnecting the SCI signals.
But also has he mentioned, voltage and frequency would help determine whether the solutions are viable here.
Thanks,
Rami
Dear Clemens,
The signals will be connected to a micro with frequency of 12MHz and 3V3. I will take a look at what you have already suggested.
Thanks a lot
Farzaneh
I chose the switches mentioned above for 5 V support. They work well at 3.3 V, but you can also consider the SN74CBTLV3257 as a 4-channel 2:1 switch.
Hello,
There is sth else that I need to know. Is it possible to connect serial ports (SCI signals) to Jtag ones(TDI/TDO)? They are using different protocols and I guess I can't connect them directly. Maybe I need a convertor in between.
Farzaneh
A switch cannot help you with this.
"SCI" is not a protocol, and I do not know which JTAG protocol you're using. A converter would be a microcontroller, but I guess you already have a microcontroller in your system. It might be possible manage the JTAG protocol with GPIOs.
Dear Clemens,
I could find out that TDO/TDI ports of the microcontroller also support de SCI signals. It has been mentioned in MICRO datasheet. Now I need only to put the MUX for connecting the lines and also disconnecting them.
Thanks a lot
Farzaneh
Dear Clemens,
Just the last question to confirm that everything is correct.
I made this circuit:
where I used the analogue switches, I need them to open or close simultanously. I've thought I could use one ontrol signal for both. Is it OK? or do I need to consider more things?
Thanks
Farzaneh