In SX Microcontrollers, SX/B Compiler and SX-Key Tool, mjcaisse wrote:

So I thought I should just back up and verify something very simple.

I'm running the LED28.src file as is. The "schematic" is just as described in the source code comments: LED adode to RC.7, cathode to 470 ohm resister and other resistor leg to groud.

I do a contol-P and it loads and runs. The LED is flashing away.

I then power off the board, remove the SXKey and power the board up. No flashy LED and the SX device gets way hot.

Just to clarify, the only items I have plugged into the SX Tech Board are:

[list]

* SX28 Chip
* LED connected to the RC.7 header and the protoboard
* 470 ohm resistor connected to the protoboard and Vss
* Power to the VDC input

[/list]


For grins I removed the two components (LED and resistor) and the SX chip gets hot when powered up without the SXKey.

Now for the fun one. This will be the comment that will jog somebody's memory (I just wish it was mine). If I put the components back like before (LED and resistor), plug the SXKey in, plug in the power and watch the LED flash.... and then remove the SXKey with the power on.... it keeps flashing and doesn't get hot.

It is acting like it is in some initial power-up state that the SXKey is able to get it past. Like... maybe when the data sheet says you don't need any external components when using the internal clock it really means don't let it float. I had a funny problem like this with a Coldfire 5282 and an "unused" pin once.

All I can say is that I must be pathetic 'cause I haven't seen any other posts will people having issues with such a simple test.


Thanks for the help!






[code]
;=======================================================================
;TITLE:         led28.src
;
;PURPOSE:       Simple Blink-an-LED example.
;
;AUTHOR:        Parallax, Inc.
;
;REVISIONS:
;  09/17/04 -   Updated to support SASM.
;
;CONNECTIONS:
;  RC.7 to LED anode.
;  LED cathode to 470 ohm resister, other leg of resistor to ground.
;
;DETAILS:
;  RC.7 is toggled high and low with a simple delay loop in-between.
;  NOTE: To simplify code, the entire RC port output latch is inverted
;  by this routine.
;=======================================================================


;-------------------------- DEVICE DIRECTIVES --------------------------

		DEVICE		SX28,OSC1MHZ,TURBO

IFDEF	__SASM  ;SASM Directives
		DEVICE		STACKX,OPTIONX
		IRC_CAL		IRC_SLOW
		
ELSE		;Parallax Assember Directives
		DEVICE		STACKX_OPTIONX
ENDIF

		RESET		Initialize

;------------------------------ VARIABLES ------------------------------
			
		Count1	EQU	$08
		Count2	EQU	$09

;---------------------------- DEBUG SETTINGS ---------------------------

		FREQ 	1_000_000
	
		WATCH	Count1,16,UDEC

;------------------------ INITIALIZATION ROUTINE -----------------------

Initialize
		;Configure port settings
		mov	rc, #%00000000		;Port C output zero
		mov	!rc,#%01111111		;Port C.bit7 output dir.

;---------------------------- MAIN PROGRAM -----------------------------

Main
;Toggle RC.7 with a delay of 64k counts in-between.

		call	delay			;delay	
		mov	W,/RC			;toggle all of RC port
		mov	RC,W				
		jmp	Main			;goto main				


Delay		clr	Count1  		;Initialize Count1, Count2	
		clr	Count2								

Loop		djnz	Count1,loop		;Decrement until all are zero		
		djnz	Count2,loop							
		ret				;then return		
[/code]

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