I have a device and the user manual has a description of the serial data communication protocol. In the manual is says. Temperature Setpoint 0x31
Write:
[00][02][AA][31][D#1][D#2][CS][CS][0D]
[AA]: [00] for SHG, [01] for THG
[D#1][D#2]:0-16000 (Units: 0.01C) For example, 50.00 C would be [13][88].
I can not figure out how to convert 13 and 88 to 50.00.
I am not sure if the SHG or THG have anything to do with it. I don't know what those mean.
Thanks!
OH! I figured it out! 1388 in HEX is 5000. That couldn't be more simple. Sorry for the stupid post! I tried so many other things but didn't think of the simplest one...
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I recently got hold of a ZX Spectrum +3 and am trying to get RS232 working with the spectrum. I’ve built a cable (‘BT’ style connector <-> DB9 serial) following the pin out of the cable (Spectrum 128 RS232 data cable) here.
The other end of the cable is connected to the PC using a USB-Serial adapter. I'm using Moserial on Linux to communicate with the Spectrum.
The cable works and I can use LLIST to print BASIC programs over the serial port, but I'm unable to get the Spectrum to read from the serial port reliably - even when enabling hardware handshaking (DTR/CTS) in Moserial.
I wrote a simple program in +3 BASIC to print received characters to the screen. It seems the first character is received OK, but the remaining characters are dropped or become corrupted.
Here is an example of what the Spectrum outputs when attempting to send 'zx spectrum' at 300 baud:
z[dot/box character]. VAL$ [box character]MOVE VAL$ VAL$ ?)
(it seems VAL$ and MOVE$ are each a single character in the Spectrum's ROM)
screenshot:
And the BASIC program which opens the serial port, and prints received characters to the screen:
10 FORMAT LINE 300
20 FORMAT LPRINT "r"
30 FORMAT LPRINT "e"
40 OPEN #4,"p"
50 PRINT INKEY$#4;
60 GO TO 50
I discovered that if I send characters one-by-one from the PC with a long enough delay between them, I can get a much more reliable output from the Spectrum. I tested this with different delays, and 80ms worked the best. I don't really want to use this approach as a solution - it's awfully slow and occasionally some characters are dropped.
Could this be an issue with the Spectrum itself? Or am I missing something in my setup? Something just doesn't seem right, I know there is a program loader for the spectrum over serial - so surely the spectrum must be able to accept serial input without a 80ms delay per character?
The ZX Spectrum Interface 1 works by bit-sampling, in a software loop, with delays, so that it can look for the start bit and then look for the other bits. There is no shift register. It's all done in software.They don't even use interrupts or some other kind of fixed external timer to generate baud rate delays.
As a result, it doesn't even start looking for a start bit until it knows you're looking for input... Now that you have an idea what's going on I'm pretty sure you've already seen the problem there? If you're sending data too fast, then your basic program doesn't even have time to go back to the receive routine to look for start bits, and start bits are going to be lost, or more likely, you're going to pick up a bit transition mid-byte and receive gibberish... So you need to make sure that there's a delay between bytes and your Spectrum is ready to receive the next byte before you start transmitting.
Hope this helps even though it's a while ago, but others will find this so...
In zx spectrum 48k, with interface 1, i must choose how the rs232 will work.
Mode t : text ->rx and tx only character in 7bit
Mode b: byte -> rx and tx full byte (8 bit)
Maybe you must chek that.
On 48k with interface 1
FORMAT "b";9600
Then , the spectrum works in 8bit data at 9600 bauds.
In your code, i dont see how will works.
My best regards.
I came across your problem as I was trying to do the same!
You need to enable RTS/CTS handshaking in your linux (PC) application, not DTR/RTS.
This works for me on my Spectrum+2:
100 REM ** Receive Test **
110 REM ** Use RTS/CTS **
120 CLS
130 FORMAT "p";9600
140 OPEN #4,"p"
150 PRINT INKEY$#4;
160 GO TO 150
There's software incompatibility between modern computers and ZX Spectrum when doing serial communication. It can be fixed, but not from Basic. The problem with RTS/CTS is that after Spectrum signals that it can't receive any more data via the CTS signal: modern UART chips will assume that the receiving computer is still able to receive cca. one buffer of data (=up to 32 bytes). But ZX Spectrum only has 1 byte buffer. So when Spectrum says its' full, it will get flooded by additional 32 bytes of data.
That is the reason anything faster then 1200 bauds will not work from BASIC. However ... I got ZX Spectrum to run reliably at 57600 and with error correction at 115200. By simply expecting up to 32 bytes after I signal the PC to stop sending data.
I've had all this working years ago with my Spectrum and the ZX Interface 1's own rs232 port, but I wrote some C program using an old Windows 386 computer.
I still have the hardware and the cables. In fact, now that I remember I had to build my own "null modem" cable and connect it from the RS232 port on the computer to the ZX Interface 1 (I have an old Sony Vaio laptop with an RS232 port).
I was even able to download TAP files to play on the real spectrum. I'll dig up what I have and get back to you.
I was working on this project : http://elm-chan.org/works/sd8p/report.html
and I failed in every possible way from the start. Now that the .Hex files have been uploaded, and the fuses written, when I plugged the SD card in, nothing happened. Nothing at all. Directly asking for a solution might be impossible here as I have no idea what went wrong. So instead I tested the speaker's positive connection with the arduino serial plotter, and I found some interesting results. The output gave some cool irregular pattern of waves,similar to what I would expect from a sound output. But there was no sound, and I suspect that it was because of the output size being too small.(60/1023 is around 0.06 volts, 200/1023 is around 0.2 volts and the bigger output at 500++ levels out, so it shouldn't produce a sound.)
So now I would like to ask whether I can change the fuses of the .hex file(or the hex file itself, but its big.) to produce a larger output. I have not much understanding in hex files or even AVR devices, so any hep at all would be useful.
Thanks in advance.
the graphs
Please let me know if any other information is needed.
Your voltage output on a GPIO pin is limited to your supply voltage, so no you probably can't fix your problem by changing the software or the fuse bits. Depending on your current supply voltage, you might be able to crank that higher, which would increase your voltage output of the PWM, but the supply voltage can only go so high without damaging the chip.
That being said, you need to disconnect the amp and speaker from the AVR and probe the output pin of the PWM and make sure that it is actually producing a signal on that pin. The plots that you posted with that amplitude look like they are nothing but random electrical noise to me.
I want to send data to a TCP 105 circuit.
The following hex command is OK to send data 123:
7F30001103 313233 45D4
Here, 313233 is hex representation of 123 and 45D4 is the CRC value.
I'm in problem to obtain this 45D4 after calculating CRC. After searching for a long time on the web, I'm getting other CRC values in different standards. But those CRC values are not being accepted by my LED display circuit.
Please help me to know how is it possible to get 45D4 from 7F30001103313233.
Thanks in advance.
The command matches an algorithm called CRC-16/CMS.
$ reveng -w 16 -s 7f30001103313233d445
width=16 poly=0x8005 init=0xffff refin=false refout=false xorout=0x0000 ch
eck=0xaee7 name="CRC-16/CMS"
This is probably the correct algorithm, as you've only given one codeword (and because I've assumed that the CRC has been byte-swapped.)
To generate code that computes this CRC, see Mark Adler's crcany tool, for instance.
I am trying to figure out how the calculate the CRC for very simple SDLC frames.
Using an MLT I am capturing the stream and i see some simple frames being sent out like: 0x3073F9E3 and 0x3011EDE3
From my understanding the F9E3 and EDE3 are the 2 byte checksums of the 3073 and 3011 since that is all that was in that frame.
using numerous CRC calculators and calculations I have been able to get the first byte of the checksum, but not the last byte (the F9 and the ED).
Using this calculator (http://www.zorc.breitbandkatze.de/crc.html):
Select CRC-CCITT
Change Final XOR Value to: FFFF
Check Reverse Data Bytes and reverse CRC result before Final XOR
Then type the input: %30%11
Which will give the output B8ED so the last byte is the ED.
Any ideas?
You are getting the correct crc16's (F9 F8, ED B8). I don't know why your last byte is E3 in both cases. This is perhaps a clue that the packets are not being disassembled correctly.
A question in my university homework is why use the one's complement instead of just the sum of bits in a TCP checksum. I can't find it in my book and Google isn't helping. Any chance someone can point me in the right direction?
Thanks,
Mike
Since this is a homework question, here is a hint:
Suppose you calculated a second checksum over the entire packet, including the first checksum? Is there a mathematical expression which would determine the result?
Probably the most important is that it is endian independent.
Little Endian computers store hex numbers with the LSB last (Intel processors for example). Big Endian computers put the LSB first (IBM mainframes for example). When carry is added to the LSB to form the 1's complement sum) it doesn't matter if we add 03 + 01 or 01 + 03: the result is the same.
Other benefits include the easiness of checking the transmission and the checksum calculation plus a variety of ways to speed up the calculation by updating only IP fields that have changed.
Ref: http://www.netfor2.com/checksum.html