You must generate the 21 registers UNLESS you are sure that two different
delays are not executed at the same time. I mean:

You call Delay1
                Delay1 calls delay2 ---> You need different registers for
delay1 and delay2

You call Delay1
You call Delay2 ---> You can use the same registers for both delays.

$+2 means (Current Address + 2)



Mauricio Jancic
Janso Desarrollos
Microchip Consultant Program Member
(54) 11-4542-3519
info@janso.com.ar
www.janso.com.ar


>>-----Original Message-----
>>From: pic microcontroller discussion list
>>[mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Aslam Jallali
>>Sent: Wednesday, August 25, 2004 3:45 PM
>>To: PICLIST@MITVMA.MIT.EDU
>>Subject: [PIC:] code question
>>
>>Hello to you
>>Using the delay generator from
>>I have generated 21 different delay routines. (I need these
>>for different LED flash sequences). The question is: do I
>>need to define 21 different temporary registers in CBLOCK?
>>i.e. see below please. What is $+2? In the manual it says
>>return program counter (see my comment beside the code line)
>>I appreciate your input & advice on this one ;-) Regards
>>
>>
>>CBLOCK 0x20   ; RAM starts at address 20h
>>D1
>>D2
>>D3
>>.
>>.
>>.
>>D21
>>ENDC
>>
>>Follwoing are the two example and then the third one is that
>>I merge them.
>>; Delay = 0.2 seconds
>>        cblock
>>        d1
>>        d2
>>        endc
>>
>>                        ;199998 cycles
>>        movlw   0x3F
>>        movwf   d1
>>        movlw   0x9D
>>        movwf   d2
>>Delay_0
>>        decfsz  d1, f
>>        goto    $+2             ; Does this mean go two lines
>>back (delay_0)?
>>        decfsz  d2, f
>>        goto    Delay_0
>>
>>                        ;2 cycles
>>        goto    $+1
>>
>>; Delay = 0.4 seconds
>>        cblock
>>        d1
>>        d2
>>        d3
>>        endc
>>
>>                        ;399999 cycles
>>        movlw   0x36
>>        movwf   d1
>>        movlw   0xE0
>>        movwf   d2
>>        movlw   0x01
>>        movwf   d3
>>Delay_0
>>        decfsz  d1, f
>>        goto    $+2
>>        decfsz  d2, f
>>        goto    $+2
>>        decfsz  d3, f
>>        goto    Delay_0
>>
>>                        ;1 cycle
>>        nop
>>
>>; delay for 0.2 and 0.4 can I call form this code upon delay
>>0.2s or ; ; 0.4s or if I add more into it
>>
>>        cblock
>>        d1
>>        d2
>>        d3
>>        d4
>>        d5
>>
>>        endc
>>
>>delay_0.2s              ;199998 cycles
>>        movlw   0x3F
>>        movwf   d1
>>        movlw   0x9D
>>        movwf   d2
>>Delay_0.2               ; note 0.2 and 0.2s
>>        decfsz  d1, f
>>        goto    $+2
>>        decfsz  d2, f
>>        goto    Delay_0.2
>>
>>                        ;2 cycles
>>        goto    $+1
>>
>>delay_0.4s                      ;399999 cycles
>>        movlw   0x36
>>        movwf   d3
>>        movlw   0xE0
>>        movwf   d4
>>        movlw   0x01
>>        movwf   d5
>>Delay_0.4
>>        decfsz  d3, f
>>        goto    $+2
>>        decfsz  d4, f
>>        goto    $+2
>>        decfsz  d5, f
>>        goto    Delay_0.4
>>
>>                        ;1 cycle
>>        nop
>>
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