Shiftout questions
Buck Rogers
Posts: 2,178
Hello!
While investigating the shiftout command, I came across the sample that proceeds to push the SN74HC595 to do mostly what it was designed for.
However that's the one part not in my inventory. I do have the SN74HC594 in stock.
Now the obvious question, does this mean that the code string, which seemed to have been written around this guy SN74HC595 8-Bit Shift Registers With 3-State Output Registers, won't work for this fellow SN74HC594 8-Bit Shift Registers With Output Registers. It seems from examining the data sheets that the parts are functionally related, but not obviously similar. The designer can't swap parts and expect the layout to work the same way.
Interestingly enough the stamp seems to be behaving as expected now.:smhair:
While investigating the shiftout command, I came across the sample that proceeds to push the SN74HC595 to do mostly what it was designed for.
However that's the one part not in my inventory. I do have the SN74HC594 in stock.
Now the obvious question, does this mean that the code string, which seemed to have been written around this guy SN74HC595 8-Bit Shift Registers With 3-State Output Registers, won't work for this fellow SN74HC594 8-Bit Shift Registers With Output Registers. It seems from examining the data sheets that the parts are functionally related, but not obviously similar. The designer can't swap parts and expect the layout to work the same way.
Interestingly enough the stamp seems to be behaving as expected now.:smhair:
Comments
The only difference is that the 594 does not have an Output Enable (OE), its outputs are always enabled. You 'might' see/notice a little twinkling if you're shifting segment data (for LEDs), but they still shift.
Hello!
It was a statement PJ.
Now the question. I don't suppose anyone from Parallax can identify the example device for Shiftout on page 438 of web-BSM-v2.2.pdf? (File not attached.):idea:
At the moment I am thinking of applying the SN74HC594 to something. And obviously, the other question is one of, "Whose part was tested was tested for that example?".
The pinouts do not agree with those of the same pin numbers on the SN74HC595. (TI designated.) I can't recall what company first announced the HC family of CMOS devices, but those part numbers are available from a number of sources. And the only one individual who does rename part numbers to support his theories on why digital logic behaves strangely, was one Don Lancaster. Fortunately he does suggest that the user study the data sheets before making any further decisions.