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Serial programmers?

L

Lessie

Jan 1, 1970
0
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
 
W

Wim Lewis

Jan 1, 1970
0
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.
 
R

Roger Johansson

Jan 1, 1970
0
Lessie said:
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

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;

http://www.speedy-bl.com/avr-prog-e.htm

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.
 
R

Roger Johansson

Jan 1, 1970
0
Roger Johansson said:
The serial programming interfaces I have seen do not use the serial
port on the computer. They use the parallell port.


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:

http://www.speedy-bl.com/adapter-e.htm

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.
 
L

Lessie

Jan 1, 1970
0
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
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.

Any ideas as to how to do that with win2000 and vb6 ?

tx
 
L

Lessie

Jan 1, 1970
0
A serial programmer for PICs can be found at

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
 
R

Rich Grise

Jan 1, 1970
0
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

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
 
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