What is the maximum baud rate than can be used with these shields and what are all the available baud rates?
What is the largest baud rate others have used these devices successfully with?
The AT instruction set v2.0.0 documentation(from http://bbs.espressif.com/viewtopic.php?f=51&t=1023) for AT+UART_DEF and AT+UART_CUR says:
Baudrate range: 110 to 115200*40 (4.608 Mega)
The datasheet for the ATmega328P shows the max baud rate @16MHz is 2Mbps so I suppose that's the theoretical maximum. I'm not sure if that will be reliable in real life. It's worth giving it a try. Please post your results. That's only if you're using hardware serial, SoftwareSerial on the Arduino supports a much lower maximum speed. I know people have reported issues using it at 115200 baud.
I've only used mine with hardware serial at 115200 just because that's the ESP8266 AT firmware default value and my application didn't require speed.
pert:
The AT instruction set v2.0.0 documentation(from http://bbs.espressif.com/viewtopic.php?f=51&t=1023) for AT+UART_DEF and AT+UART_CUR says:The datasheet for the ATmega328P shows the max baud rate @16MHz is 2Mbps so I suppose that's the theoretical maximum. I'm not sure if that will be reliable in real life. It's worth giving it a try. Please post your results. That's only if you're using hardware serial, SoftwareSerial on the Arduino supports a much lower maximum speed. I know people have reported issues using it at 115200 baud.I've only used mine with hardware serial at 115200 just because that's the ESP8266 AT firmware default value and my application didn't require speed.
I did try setting the baud rate of the ESP higher than 115200, and in the setup function for the library, and I could seem to get the page to download from the arduino to my web browser.
Not sure if I was doing anything else wrong though.
I have used this web page to compress all my html and javascript:
https://htmlcompressor.com/compressor/
But I am having trouble with my web page taking longer to download from the arduino than I would like - about 15 seconds or so.
I have incorporated a message along the lines of "be patient" that display immediately and then is hidden ones the rest of the page is downloaded and rendered.
But are there any other trick that people have used to speed up the process further?
boylesg:
I did try setting the baud rate of the ESP higher than 115200, and in the setup function for the library, and I could seem to get the page to download from the arduino to my web browser.
How high?
boylesg:
But are there any other trick that people have used to speed up the process further?
What I found is you want to assemble as much as possible of your page at once and send it all at once rather than sending it in a bunch of small parts. I've been mostly using them standalone lately, rather than running AT firmware connected to a standard Arduino and there's a limit to how much you can send at a time, which I haven't found documented anywhere after a bunch of searching, I'm just sending it whenever it gets over 1000 characters long. I'm guessing it's the same with the AT firmware.
Even with that it still seems slower to load than it should be. Using in AP mode doesn't seem to make a difference. Luckily I haven't used it for an application where speed is important yet.
pert:
How high?
What I found is you want to assemble as much as possible of your page at once and send it all at once rather than sending it in a bunch of small parts. I've been mostly using them standalone lately, rather than running AT firmware connected to a standard Arduino and there's a limit to how much you can send at a time, which I haven't found documented anywhere after a bunch of searching, I'm just sending it whenever it gets over 1000 characters long. I'm guessing it's the same with the AT firmware.Even with that it still seems slower to load than it should be. Using in AP mode doesn't seem to make a difference. Luckily I haven't used it for an application where speed is important yet.
I tried 230400 bps and it didn't seem to work.
I solved my very slow download time thus:
I have the web page in a file on the SD card and I was reading the html and sending it out a line at a time.
That meant character analysis to find the end of line markers (\n and \r) and it was primarily responsible for slowing it down.
On top of that I was looking for markers in two lines of html in which to insert a RTC battery voltage value, thus further slowing things down.
What I ended up doing was splitting my html file into two separate files with the bulk of the html in the first file and the last dozen or so lines (with the markers) in the second file.
The first file with most of the html and javascript is read 2000 bytes at a time and output 2000 bytes at a time to the wifi client.
Then only the second file is read one line at a time so that I can find the text markers and replace them with the battery voltage.
I managed to get the web page download time down from over 50s to about 13s