Been trying the (terrific) 74HC595/Max-msp code on this site:
He mentions at the bottom of the text:
"It is evident that this may be an inefficient means of updating the three shift registers, because three bytes must be sent in order to change a single bit of information output. This may suffice in many situations. But it is possible to use a numbering prefix (1 to 3) to control the register."
But i cant really figure out how to get the numbering prefixes to work.
My interpretation is that you send out the byte from max/msp with a specific prefix before the byte, like so: 100000000 - to send out to register 1 (300000000 for register 3), and then 1 = Serial.read - if 1 is recieved read the code, else do nothing (or something).
Am i totally wrong with understanding this?
Hi,
it doesn't really matter wether you send 1 or 3 bytes down the wire to the arduino.
There is only a soft limit of 64 bytes in a single report over the specific USB-Hardware used here.
The USB-to-Serial- driver will always send 64 bytes over USB. The FTDI-hardware on the ardunio knows how to extract the actual user-data from a packet.
Eberhard
Thanks for the good info, thats good to know!
But what if i want to send info to just One of my IC's, reaching it thru using a prefix, like in the URL above?
(instead of sending out all bytes in one row)
Hi,
it doesn't really matter wether you send 1 or 3 bytes down the wire to the arduino.
There is only a soft limit of 64 bytes in a single report over the specific USB-Hardware used here.
The USB-to-Serial- driver will always send 64 bytes over USB. The FTDI-hardware on the ardunio knows how to extract the actual user-data from a packet.
Eberhard