In SX Microcontrollers, SX/B Compiler and SX-Key Tool, tdg8934 wrote: All, As a test I wired up (2) 74HC138s and cascaded them for 16 LED outputs (too bad the Professional Development Board LEDs want to see +5v - had to wire up 16 negative input LEDs/resistors). I hardwired the A B C D inputs from the cascaded 74HC138's into either +5vdc or GND and saw the appropriate individual LED turn on as it should. I then took RA from the SX-28 and disconnected it from the LED Display board and connected it to the inputs on the cascaded 74HC138s. I WAS able to not have to use [b]INC Row[/b] in the routine below (from previous 6232c.sxb attachment) - but INSTEAD I could use [b]Row = 8[/b] and I saw LED 8 turn on. [color=blue>The]Row = 8 commented out (and [b]INC Row[/b] not commented) which is how it works on the LED Display Board.[/color] [code] SUB DELAY_MS IF __PARAMCNT = 1 THEN ' byte parameter? tmpW1 = __PARAM1 ELSE tmpW1 = __WPARAM12 ENDIF DO PAUSE 1 [b]INC Row[/b] ' Since Row is RA there are only 4 bits anyway, so no need to limit the value (This works identical to Interrupt routine) '[b]Row = 8[/b] '--> Can't set Row to a single value on this LED display board (does work on 2 cascaded 74HC138s with 16 LEDs) ??? DEC tmpW1 LOOP UNTIL tmpW1 = 0 ENDSUB [/code] This tells me that SX/B can use a statement like [b]Row = 8[/b] (as I have also seen in other SX/B example coding) This leads me to believe that the A B C D inputs on the Display board (although going through a buffer first before the 74HC138 - as shown in the manual/datasheet schematics), doesn't work as I would think. What we know is that the [b]INC Row[/b] command works on this board but the [b]Row = 8 [/b](or some other # between 0 and 15) does not. Since I had blown some FETs on this display board earlier (messing with the code), I thought perhaps a buffer or 74HC138 got damaged or something (which I almost didn't buy because the [b]INC Row[/b] did work on this LED Display board). I had boughten a second LED Display board that had never been powered up. I wired in power and the cable to the SX-28 on the Professional Developement Board (PDB) and the code using the INC Row worked as it did on the other board but the Row = 8 did not work (as it did not work on the other board). This tells me that both LED Display boards are working (with the exception of some burnt out FETs on my "developing" current board. I moved back to the "developing" LED Display board and wired it back up to continue this investigation. [color=blue>HERE][/color] I don't know why these boards (which use buffers and cascaded 74HC138s) can not see a [b]Row = xx[/b] but an [b]INC Row[/b] works. However, using 2 standard cascaded 74HC138's [b][color=red>both]and[/color] INC Row[/b] does work as it should. I have gotten no help from the manufacturer on this either (in China) - [url=http://www.sureelectronics.net/goods.php?id=147]http://www.sureelectronics.net/goods.php?id=147[/url] 6432 Manual/datasheet: [url=http://www.sureelectronics.net/pdfs/DE-DP030_Ver1.0_EN.pdf]http://www.sureelectronics.net/pdfs/DE-DP030_Ver1.0_EN.pdf[/url] Similar board (6416) this was developed from (a bit more information in the datasheet): [url=http://www.sureelectronics.net/goods.php?id=146]http://www.sureelectronics.net/goods.php?id=146[/url] 6416 Manual/Datasheet (similar board): [url=http://www.sureelectronics.net/pdfs/DE-DP029_Ver1.0_EN.pdf]http://www.sureelectronics.net/pdfs/DE-DP029_Ver1.0_EN.pdf[/url] Comments????? ---------- End of Message ---------- You can view the post on-line at: http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=273480#m275016 Need assistance? Send an email to the Forum Administrator at forumadmin@parallax.com The Parallax Forums are powered by dotNetBB Forums, copyright 2002-2008 (http://www.dotNetBB.com)