DS1307 on an SX28 PDB (working) vs SX48 protoboard (not working)

T&E Engineer · 2009-11-03 01:41

I took JonnyMacs DS1307 code and just modified the DEVICE line for an SX48 vs the default SX28. See attached.

I can get the DS1307 code to run fine on my PDB with an SX28 to Hyperterminal 38400. However, if I run the TX, RX, SCL and SCA from the PDB to RA on an SX48 protoboard, sometimes I get strange chars on Hyperterminal and sometimes nothing at all happens. I first thought it was a Baud issue but lowering it down to 19200 and 9600 had no effect.

I also ran a ground wire from the PDB to VSS on the SX48 protoboard. I also used a 4 MHz resonator.

Is there anything else uniquely different between the SX28 and SX48 that I am not seeing here?

Thanks.

Sens-a-Dat · 2009-11-03 23:23

Personally with the SX48, I have had difficulty getting the PIN assignment commands to work and ended up using an initialize routine to set the port settings. An example from one of my programs is below. Maybe doing a similar thing for your program will resolve the issue.

ASM
  MODE $09                ; WKPND_B
  MOV !RB,#00000000B      ; clear pending Port B detections


  MODE $0A                ; WKED_B
                          ; 0 = selects rising  edge detection
                          ; 1 = selects falling edge detection
  MOV !RB,#11111111B      ; set high-to-low detection for all Port B pins


  MODE $0B                ; WKEN_B
                          ; 0 =  enable pin for interrupt
                          ; 1 = disable pin for interrupt
  MOV !RB,#11111111B      ; 


  MODE $0C                ; ST_B/C/D/E
                          ; 0 =  enable Schmitt Trigger
                          ; 1 = disable Schmitt Trigger
  MOV !RB,#11111111B    
  MOV !RC,#00000001B     ; enable 1-7 as Schmitt-Trigger
  MOV !RD,#00000000B     ; enable all inputs as Schmitt-Trigger
  MOV !RE,#00000000B     ; enable all inputs as Schmitt-Trigger


  MODE $0D                ; LVL_A/B/C/D/E
                          ; 0 = Sets pin to CMOS
                          ; 1 = Sets pin to TTL
  MOV !RA,#    1111B       ; set 1-3 inputs to TTL levels
  MOV !RB,#11111111B    ; set 1-5,7 inputs to TTL levels, 6 to CMOS
  MOV !RC,#11111110B    ; set 1-7 inputs to TTL levels, 0 to CMOS
  MOV !RD,#11111111B    ; set all inputs to TTL levels
  MOV !RE,#11111111B    ; set all inputs to TTL levels


  MODE $0E                ; PLP_A/B/C/D/E
                          ; 0 =  Enable internal pull-up resistor
                          ; 1 = Disable internal pull-up resistor
  MOV !RA,#    0000B         ; do not use internal weak pull-up resistor
  MOV !RB,#00000000B   ; do not use internal weak pull-up resistor on 0-3 and 6-7
                                     ; internal pull-ups for 4 & 5
  MOV !RC,#00000000B    ; do not use internal weak pull-up resistor
  MOV !RD,#00000000B    ; do not use internal weak pull-up resistor
  MOV !RE,#00000000B    ; do not use internal weak pull-up resistor for 0-6


  MODE $0F                ; TRIS_A/B/C
                            ; 0 = Sets pin to output mode
                            ; 1 = Sets pin to input (High-Z) mode
  MOV !RA,#    0000B       ; set 0-7 as outputs
  MOV !RB,#11110111B   ; set 0-2 & 4-7 as Hi-Z inputs
                                     ; and pin 3 as output
  MOV !RC,#11111110B    ; set 0 as output, 1-7 as Hi-Z inputs
  MOV !RD,#11111111B    ; set 0-7 as Hi-Z inputs
  MOV !RE,#11111111B    ; set 0-7 as Hi-Z inputs


  MOV !OPTION,#01000000B    ; Register $01 is W
                                                ; RTCC roll-over interrupt off
                                                ; Prescaler assigned to WDT
                                                ; Prescaler = 1:1

ENDASM

DS1307 on an SX28 PDB (working) vs SX48 protoboard (not working)

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