need serial console help. DVR

K

korin1

Young grasshopper
Aug 27, 2017
45
8
hi guys, im a pretty new to jtag\uart
right now i am trying to connect to a device via uart , but when opening putty to the COM i am seeing some gibberish,
my setup is like so , 3 cables to the uart on the board , 1 ground (black) 1 tx (white) 1 rx (green), which they are connected to rs232 which rs232 is connected to usb to pc, black (ground) goes to pin 5 , white (tx) goes to pin 2 , green (rx) goes to pin 3


hopefully one of u can help me out :)
thanks
 
Some possibilties to try:
Your PC serial interface cable / device (eg a USB to TTL serial convertor) is connecting to an RS232 interface on the DVR. These are quite different signal levels.

Your DVR TTL serial interface is connecting to a PC RS232 cable / device. These are quite different signal levels.

Your interfaces in the DVR and the serial cable / device are compatible, but the baud rate is incorrect. A common value is 115,200 with 8 bits, no parity.

You have the GND and RX swapped.

*edit* I can see from your last pic that it looks like you are connecting to a PC RS232 cable (the DB9 connector is the clue).
These use bipolar signals, +-3 to +-15 V signals
Common on a DVR are TTL level unipolar signals, 0- 3.3v
For this you'd need a TTL to serial convertor, eg a PL2303-based device.
 
alastairstevenson said:
Some possibilties to try:
\
Click to expand...
hi, thanks alot for replying back

i did not quiet understand what u mean by saying "Your PC serial interface cable / device (eg a USB to TTL serial convertor) is connecting to an RS232 interface on the DVR. These are quite different signal levels."
what do i need to look for?

"Your interfaces in the DVR and the serial cable / device are compatible, but the baud rate is incorrect. A common value is 115,200 with 8 bits, no parity"
first think i've tested was 115200 with 8 bits
then i try all serial speeds , same result gebrish (different gebrish but still gebrish :D)

You have the GND and RX swapped
i dont think so, i've checked like 4 times
 
It does look like you have a PC RS232 interface connecting to a DVR TTL serial interface.
You can't do that - they use quite different signal levels and are not compatible.

If so, what you need on the PC is a 'Serial TTL to USB convertor'.
A common type which you will find in large numbers on eBay is a 'PL2303HX-based serial TTL to USB convertor'
 
alastairstevenson said:
It does look like you have a PC RS232 interface connecting to a DVR TTL serial interface.
You can't do that - they use quite different signal levels and are not compatible.

If so, what you need on the PC is a 'Serial TTL to USB convertor'.
A common type which you will find in large numbers on eBay is a 'PL2303HX-based serial TTL to USB convertor'
Click to expand...
well i've watch this video (which apparently use rs232)
i do have an rs232 connected to the pc via usb,
the TTL from the board is connect to this upload_2017-8-28_1-6-15.png (to the back side of it to pin 2,3,5) and this (white one) rs232 female is connected to this > upload_2017-8-28_1-3-52.png which is connected to the pc via usb.

do u think it might be the problem why it cant output regular text ?
 
Last edited:
 
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alastairstevenson said:
Not all of the above are suitable
Click to expand...
hi,
im trying to learn i've guessed that some are not suitable, could u tell me which one is suitable and which one is not ?
that would also help other ppl to understand if their stuff doesn't work
thanks again !
 
korin1 said:
can this FTDI FT232RL USB works?
like one of these SparkFun FTDI Basic Breakout - 3.3V - DEV-09873 - SparkFun Electronics ?
Click to expand...
Requires a custom cable, bad reputation for driver quality and features.
korin1 said:
or this
Pocket AVR Programmer - PGM-09825 - SparkFun Electronics
Click to expand...
It's a programmer - not a TTL serial to USB convertor.
korin1 said:
or this
RS232 Board SP3232 RS-232 UART TTL Transceiver Evaluation Development Module Kit | eBay
Click to expand...
That might work - if you already have a genuine RS232 port on the PC, and the right form of connecting cable (modem, null modem).
korin1 said:
or this

CP2102 USB 2.0 to UART TTL 6PIN Module Serial Converter Adapter Blue+Silver LW | eBay
Click to expand...
That should work, according to the product specs. For me at least, the CP2102 drivers are an unknown quantity.
korin1 said:
or this

USB to TTL Serial Cable - Debug / Console Cable for Raspberry Pi ID: 954 - $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Click to expand...
That looks like a PL2303HX based product and should be OK.
 
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alastairstevenson said:
Requires a custom cable, bad reputation for driver quality and features.

It's a programmer - not a TTL serial to USB convertor.

That might work - if you already have a genuine RS232 port on the PC, and the right form of connecting cable (modem, null modem).

That should work, according to the product specs. For me at least, the CP2102 drivers are an unknown quantity.

That looks like a PL2303HX based product and should be OK.
Click to expand...

after month of waiting for the shipment
i got PL2303HX USB To RS232 TTL Auto Converter Module Converter Adapter For arduino | eBay

and
USB To RS232 TTL UART PL2303HX Auto Converter USB to COM Cable Adapter Module | eBay

and the result is the same.. :(
like exactly the same.

what am i doing wrong ?
 
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UPDATE
its working with USB To RS232 TTL UART PL2303HX Auto Converter USB to COM Cable Adapter Module | eBay
i just set it to 115200 bits and i was able to see :)
thanks alot

new question
i have a dvr SA-8200AHD-1(MM) which does not work properly nothing boot up, when powering it on it just beeping non stop.
when i connected my self to uart on the board on all bits possible (expect 115200) it shows me white question marks ???? and symbols one after another.
when changing the bit to 115200 it output me (while beeping . . .) blank spaces, not letters no nothing.
anyidea what could that be ? and how can i approch this problem ?
 
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