I was just wondering how serial programmers work, i.e. we need two lines, one for clock, and one for data. Which serial line is used to send the clock to the device? I assume the data uses RD/TD
- posted
19 years ago
I was just wondering how serial programmers work, i.e. we need two lines, one for clock, and one for data. Which serial line is used to send the clock to the device? I assume the data uses RD/TD
Most serial programmers use the serial port as if it were just a very strange parallel port. The modem control and flow control lines (DTR, DSR, RTS, CTS, RI, CD) can be set and read individually, and that's enough bits of I/O there to program something. They might not even use RxD / TxD.
Another advantage of the serial port is that you can usually draw enough current from it to power the chip while you're programming it.
-- Wim Lewis , Seattle, WA, USA. PGP keyID 27F772C1
The serial programming interfaces I have seen do not use the serial port on the computer. They use the parallell port.
Look at this serial programming interface for atmel microprocessors;
The hardware consists of a few wires, more than 2 though, from the parallell port to the microprocessor.
To me "a serial programmer" means that it uses serial technology into the device, but it doesn't mean that a standard serial interface as in serial ports are used.
-- Roger J.
After seeing Win Lewis answer I can add, yes sometimes the serial port is used too, but it often gets more complicated, like in these adapters for the same devices:
The bottom line is, the "serial" in serial programmers is not saying anything about what ports you use on the computer, it is about how data is programmed into the device. And the communication does not follow the regular serial interface protocol.
-- Roger J.
Sorry, I forgot to mention what I was talking about, I meant pic programmers (microchip) which connect from the serial port of the pc. Here is my problem. If I have visyal basic I can use MSComm object to read and send characters to the serial line. The problem, as far as I can see, is the clock, as there is no extra send/receive line
Any ideas as to how to do that with win2000 and vb6 ?
tx
If you're using "the serial port" and sending and receiving characters with a comm DLL, then no "clock" is needed - the receiving device figures out the 1's and 0's based on the start bit, n data bits, and stop bit, and all of the bits are sent at some previously-agreed-on rate.
So we might be talking apples and oranges here. It sounds like you have a whole development kit, which talks to the computer with a comm line.
The others seen to think you're referring to the chip itself, which might or might not be using a UART. To bitbang serial data to a chip that has "data" and "clock" lines, you have to wiggle individual bits.
Hope This Helps! Rich
A serial programmer for PICs can be found at
petrus bitbyter
"Lessie" schreef in bericht news:d266ss$1cg$ snipped-for-privacy@domitilla.aioe.org...
hi, thanks, maybe this is what I need, can you be more specific with the link, as it seems to be an entry point of a random webring tx
"Lessie" schreef in bericht news:d29k2h$m4a$ snipped-for-privacy@domitilla.aioe.org...
It isn't. Details of the programmer are on
petrus bitbyter
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