Archive for the 'SX' Category

SXy I/O

Sunday, February 4th, 2007

I received the shipment of SX goodies I ordered from Parallax on Friday, so on Saturday I quickly soldered some female headers onto the SX48 proto board (a VERY nice little board! – and is that TQFP SX48 TINY!) and quickly ported my 74HC595 I/O expander code to it from the SX28 (very tough to do… just changed the “DEVICE” line).

It works great.

While working on some code for a client, I left a test program running that displayed a 32 bit counter on the 32 status LED’s on my output board… I left it running for hours :)

SX is good for you…

Wednesday, January 31st, 2007

Sorry.

I could not resist.

But the fact is, I am finding the SX Tech Tool kit LITE I won in an ebay auction (it came without a key ring, perhaps the seller bought the items before it was included) to be a fascinating toy.

Yes, the memory capacity is limited.

True, the native instruction set is very primitive – although the IDE’s assembler tries hard to hide it with “instructions” (essentially built in macro’s) that are far more orthogonal and civilized that actually emit two native instructions; this is generally an excellent approach, with only two major gotcha’s:

  1. You have to check the listing file to see how many instructions you are actually using; so be very careful if you are trying to make very precisely timed deterministic code
  2. Be very careful of using the W register with native instructions with the “new” instructions – a LOT of the “new” mnemonics end up clobbering the contents of W

I also took a quick peek at SX/B – and I was pleasantly surprised. It is a more capable small Basic compiler than I thought it would be! Frankly, I far prefer Spin, but SX/B is an excellent way for people new to microcontrollers to get their feet wet – and let’s face it, the SX architecture is NOT suitable for C compilers. I shudder to think what the code generator would look like. Personally, I’ll stick with the excellent assembler.

But guess what… even with all those limitations… I bought a second SX Key, a Key Ring, five SX48 Proto boards and ten SX28 Dip’s (to accompany the two Sceanix labeled SX28’s I have). I think the SX’s are going to make excellent high speed I/O coprocessors for some Propeller projects I am slowly (very slowly… due to working too much for the past few months) working on.

Stay tuned!