I'm new and I just want to know if we can use more than 2 Serial comms in nodemcu by using Software Serial.. I m currently using 3 modules which need serial communication and I want to use them with a single Nodemcu. Is it possible?
I'm trying to use GPIO 4 and 5 for one serial Comm
and Rxd2 and Txd2 for second serial.
will it work?
This won't work.
Although there are two UARTs(0 and 1) available to NodeMCU, UART 1 is not capable of receiving data and is therefore transmit only.
For reference: https://nodemcu.readthedocs.io/en/latest/en/modules/uart/
Related
Using pin 26 for ADC seems to be discouraged in Toit.
From what I can see on https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/adc.html pin 26 should have an ADC converter, so what is the reason for that?
The ESP32 is limited around ADC2:
Since the ADC2 module is also used by the Wi-Fi, only one of them could get the preemption when using together, which means the adc2_get_raw() may get blocked until Wi-Fi stops, and vice versa.
Therefore I suggest using ADC1-pins if WiFi is used for connectivity.
Since All ADC2 Pins Can't be used while using WIFI, You can use ADC1
GPIO32 ADC1_CH04
GPIO33 ADC1_CH05
GPIO34 ADC1_CH06
GPIO35 ADC1_CH07
GPIO36 ADC1_CH0
GPIO39 ADC1_CH03
Check this video to learn more about esp32 pins and assigned pirepherals:
https://www.youtube.com/watch?v=LY-1DHTxRAk&t=546s
I am trying to use mcp3428 analog to digital converter for three channels voltmeter. Is there any sample code for mcp3428 to start with? I found one just for one channel, but I really want to use three out of four available channels. I have no idea how to pull data from different channels. I am working with arduino.
Assuming you can properly read out channel 1:
Page 18 of the datasheet here describes this. You need to change bits 5-6 in the configuration register
00 = Select Channel 1 (Default)
01 = Select Channel 2
10 = Select Channel 3 (MCP3428 only, treated as “00” by the MCP3426/MCP3427)
11 = Select Channel 4 (MCP3428 only, treated as “01” by the MCP3426/MCP3427)
This is done by using the I2C commands in the Arduino Wire Library here. The idea here is that you issue a write command to the configuration register and set bits 5 and 6 to the associated channel, then you do a normal read (again, assuming you have figured out how to properly read channel 1 data).
I am currently working on a script in docklight v2.0.
My setup is the following:
I have a splitter connected in the USB port of my PC.
That splitter is connected on a wire on which a communication is made between 2 devices.
Docklight is connected on the USB port and receives all the information transmited through that wire.
I have a script on docklight set up to put every byte in a buffer once docklight sniffs them.
My script is coded using the functions in Docklight and VBScript.
The problem I have is the following:
I put all the bytes in the same buffer, that mixes up the messages from both devices and it becomes impossible to analyse them.
What I need to do:
I need to know which byte comes from which device, Docklight is already able to do so, but I need to do that in my script so I can put the bytes in 2 different buffers to treat the data properly.
Using the fonction DL.OnReceive_GetChannel() solved my problem.
I'm currently working on a project which involves dealing with a HW device tailor-made for this purpose.
The device will serve the purpose of sending certain data via serial port (COM1, for instance). The data it is supposed to send doesn't matter that much.
I already have some knowledge regarding Windows serial port communication. CreateFile, WriteFile, and so on... BUT...
There is one "engine" on the device, which will send me the data when I ask it to, and in order to do so, I need to send there a signal (10101010) the rate of which will indicate the clock rate of that device "engine".
Here comes the explanation of how this device work. It gets a signal to send data through one pin. I'm supposed to send there 0 for start, 1 for end. Then, after this, it will watch some other pin for signal, sample it, and based on the frequency of ones and zeroes I send to it, it will start sending data via the thrid pin.
My questions are:
How to access individual pins of COM port?
How to manage the frequency and any delays I will need by myself?
I think that maybe I will have to do on this in kernel more by use of device drivers which will have to be developed.
There is an easier way. The COM port will send out the signal of alternating 1s and 0s if you just send a 0xAA byte.
I'm working on a script to map servers that are connected into our switches and routers. I have it working to map layer two ports, using the algorithm listed at http://www.cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a00801c9199.shtml to pull out the MAC addresses.
Layer 3 ports are another matter. These are ports that don't show up in the 'sh vlan' command on a router/layer 3 switch. Ideally, I'd like to use the MAC addresses present in these ports, underlying the layer 3 connection, as that's a bit more 'permanent' than the IP address - these do show up in the MAC-address table on the device. However, the fact that these ports don't have an associated VLAN, and that the MAC retrieval via SNMP is VLAN-indexed, makes it quite difficult.
I've been banging my head against this for about a week or so, but nothing I try/find seems to allow me to get the non-VLAN MAC addresses. Is it possible to map the layer three ports this way, or will I need to use layer 3 (IP address) mapping?
If you are connected via layer 2 to the device, you could just use a ping on the layer 3 address to generate an arp lookup and then look in the arp cache for the mac... This would work for any layer 3 port, even logical ports like the layer 3 version of Portchannels.
This is probably the easiest way.
If you want to be 100% in the realm of SNMP:
To get the interface table for that device, walk the below oid. It will return
the list of all interfaces on that device. This should work on any device (even a server) runnning a SNMP agent:
.1.3.6.1.2.1.2.2.1.2
This will give you a list of interface numbers (last digit in OID), and the interface descriptions. It works for SVI and physical interfaces, not sure about logical types other than SVI.
Then for each interface, to get it's mac (where x is the value in the interface table):
.1.3.6.1.2.1.2.2.1.6.x
This gives you the mac. (Leading 0's can be truncated on some devices.)
However, you will need atleast 1 layer 3 address on each device to do the snmpwalk and get.
If you just want all the macs, then walk this oid:
.1.3.6.1.2.1.2.2.1.6
I use this approach to do something similar on a large network.