> Sorry if I sounded dismissive of your post, it wasn't my intention

No worries

> lets say that I have five analogue sensors connected to the same
> ADC but different channels, how do you handle that?

Because each module has at least one PIC, there are more than enough
ADC i/p, so you'd cycle them with the adcon register. My system is on
a general 1Hz tick so sampling speed is not an issue. I can either let the
probes sample on every tick or interrogate them remotely on demand.
I do have a buffer system as your friend suggested. The sampling frequency
and buffer size are user-definable. For many applications the voltage
being measured does not change very quickly, eg ambient temperature
or the sensor itself doen't react very quickly

Additionally, the core generates a 10ms tick. This is received by all
sensors/modules and is used, together with the numeric value of their
addresses, to separate communication packets. So for example, and
very basically, if a module has information to send, it counts the number
of 10ms ticks it receives after the 1Hz tick, and when that count equals
its assigned address (based on when it was detected on power-up), it
transmits

> I want to make the sensor an individual entity but the five sensors are
> really five ADC channels which are part of the same ADC

In my case an individual sensor is selected with a text string. Here's a
partial list of analogue commands. There is a higher set to address a
particular module. For example AN01 to AN04 are one module, AN05
to AN08 are another and so on, so the core does a /4 to find which
module the required ADC is on. All strings are terminated with ^

; ANA                               read all
; ANC                               cancel all AN commands
; AN## C                            cancel AN## command
; AN## S vvvvv                      set scale of AN##
; AN##                              read AN##
; ANA mmm                           read all every mmm
; AN## mmm                          read AN## every mmm
; AN## tttt                         read AN## at tttt each day
; ANA tttt                          read all at tttt each day
; AN## R mmm                        record AN## every mmm
; ANA R mmm                         record all every mmm
; AN## Gvvv [mmm]                   read AN## [every mmm], alert if AN## >
vvv
; AN## Lvvv [mmm]                   read AN## [every mmm], alert if AN## <
vvv
; AN## Evvv [mmm]                   read AN## [every mmm], alert if AN## =
=3D
vvv
; AN## [G][L][E]vvv [mmm] [W][P]    send every mmm to web, alert to phone

The ## in AN## is detected and evaluated as below. You'll appreciate
there are many hundreds of lines of code to cover all the commands. To
relieve the core (an 18F4550) of a lot of donkey work, each module
controller (an 18F1320) has its own copy of what could be described as
an interpreter. Some alterations are made to suit the module - AN for
analogue, RY for relay, IO for digital, HV, LV for high and low voltage
(which also have commands for switching input dividers) and so on

Once a value has been got by the ADC, it's converted to a text string
and compiled, along with an echo of the command, phone number and/
or email address etc, time stamp, then transmitted to the core, which in
turn sends it to a cellular modem. For other modules a pin status might
be found, rather than a voltage. Such as a relay on/off or an input L/H

Hope that helps. It sounds complicated but actually, as with all s/w, it's
just a management plan and a collection of very small jobs

Joe

;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D

tst_ac   lfsr    fsr0,r_byte+.2 ;input string source, skip AN

         movf    indf0,w
         xorlw   "A"          ;test for ANA (measure all)
         skpnz                ;no
         goto    msr_all      ;yes

         movf    indf0,w
         xorlw   "C"          ;test for ANC (cancel all)
         skpnz                ;no
         goto    cncl_all     ;yes

;next two characters must be device number

         movf    postinc0,w
         andlw   0x0f         ;reduce device ## to one hex byte
         movwf   temp0

         clrc                 ; ## x 10 =3D x 2 + x 8
         rlcf    temp0,w
         movwf   dev_no
         rlcf    temp0
         rlcf    temp0
         rlcf    temp0,w
         addwf   dev_no

         movf    postinc0,w
         andlw   0x0f         ; + units
         addwf   dev_no       ;dev_no =3D device number, 1-4

         movf    postinc0,w
         xorlw   "^"          ;test for AN##^
         skpz                 ;yes
         bra     tst_let      ;no, test for letter

         call    msr_one      ;get value
         call    mul16x8      ;convert ADC to string
         goto    message      ;compose message and send
                              ;exits to wait_ser

;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
;        Measure one AN
;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

msr_one  movf    dev_no,w     ;select AN channel
         xorlw   .1
         bnz     anch2

         bcf     adcon0,chs0
         bcf     adcon0,chs1
         bcf     adcon0,chs2
         goto    sample

anch2    movf    dev_no,w
         xorlw   .2
         bnz     anch3

         bsf     adcon0,chs0
         bcf     adcon0,chs1
         bcf     adcon0,chs2
         goto    sample

anch3    movf    dev_no,w
         xorlw   .3
         bnz     anch4

         bcf     adcon0,chs0
         bsf     adcon0,chs1
         bcf     adcon0,chs2
         goto    sample

anch4    bsf     adcon0,chs0
         bsf     adcon0,chs1
         bcf     adcon0,chs2
         goto    sample

sample   bsf     adcon0,go_done ;start conversion
         nop
         btfsc   adcon0,go_done
         bra     $-2

;transfer result

         movf    adresl,w
         movwf   temp4
         movf    adresh,w
         movwf   temp3
         return

;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
;        Convert ADC to user units
;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

;(ADC * resolution)/1000

;   temp3:4  (MSB:LSB)  =3D ADC - 10-bit
;   temp5               =3D resolution - 8-bit
;   temp0:1:2(MSB:LSB)  =3D 24-bit product
;   temp6               =3D bitcount

;Multiply ADC reading * resolution

mul16x8  clrf    temp0        ;clear result area
         clrf    temp1
         clrf    temp2

         mov     0x01,temp3
         mov     0xb8,temp4

;         lfsr    fsr0,reso1   ;get resolution of device
;
;         decf    dev_no,w
;         addwf   fsr0l
;
;         movlw   low(indf0)   ;1 bit of ADC =3D xx units
;         movwf   temp5

         mov     .5,temp5
         clrf    temp7

;http://www.piclist.com/techref/microchip/math/mul/16x16bfsd.htm
; n_2 : n_1 * n_4 : n_3 -> q_4:q_3:q_2:q_1
; temp3:temp4 * temp7:temp5 -> temp8:temp0:temp1:temp2

         clrf    temp8        ;not needed in result
         clrf    temp0
         clrf    temp1
         clrf    temp2
         bsf     temp1,7

m1       rrcf    temp3
         rrcf    temp4
         skpc
         bra     m2
         movf    temp5,w
         addwf   temp0
         movf    temp7,w
         skpnc
         incfsz  temp7,w
         addwf   temp8

m2       rrcf    temp8
         rrcf    temp0
         rrcf    temp1
         rrcf    temp2
         skpc
         bra     m1

;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
;        Find digits
;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

; Dividend - temp0:temp1:temp2 (MSB:NSB:LSB) =3D (ADC * resolution)
; Divisor  - temp3:temp4       (MSB:LSB)     =3D 1,000 (03E8)
; Bit counter - temp8
; Remainder   - tmp_valh:tmp_vall
; Quotient    - temp5:temp6:temp7

div2416  clrf    tmp_vall     ;clear remainder
         clrf    tmp_valh

ok2div   movlw   0x03
         movwf   temp3        ;set divisor =3D 1,000
         movlw   0xe8
         movwf   temp4
         movlw   .24
         movwf   temp8        ;bit count

lpu2416  rlcf    temp2        ;shift left divider to pass next bit to
remainder
         rlcf    temp1        ;and shift in next bit of result
         rlcf    temp0

         rlcf    tmp_vall     ;shift carry into remainder
         rlcf    tmp_valh

         rlcf    temp8        ;save carry in counter

         movf    temp4,w       ;subtract divisor from remainder
         subwf   tmp_vall
         movf    temp3,w
         skpc
         incfsz  temp3,w
         subwf   tmp_valh,w   ;keep byte in W until borrow tested

         skpnc                ;if no borrow
         bsf     temp8,0      ;set bit 0 of counter (saved carry)

         btfsc   temp8,0      ;if no borrow
         goto    uok46ll      ;else

         movf    temp4,w      ;restore remainder if borrow
         addwf   tmp_vall
         movf    tmp_valh,w   ;read high byte of remainder to W
                              ;to not change it by next instruction

uok46ll  movwf   tmp_valh     ;store high byte of remainder
         clrc                 ;copy bit 0 to carry
         rrcf    temp8        ;and restore counter
         decfsz  temp8        ;decrement counter
         goto    lpu2416

;         clrc
         rlcf    temp2        ;shift in last bit of result
         rlcf    temp1
         rlcf    temp0

;         movf    temp1,w        ;1000s in hi:lo
;         movwf   tmp_valh
;         movfw   temp2
;         movwf   tmp_vall

;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
;        Make ASCII number string for message
;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
;        Convert 8-bit data to 3-digit ASCII
;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

;data (1000s) to convert is in temp2

bin2bcd  ;movlw   .13
         ;movwf   temp2
         ;movlw   low(.500)
         ;movwf   tmp_vall
         ;movlw   high(.500)
         ;movwf   tmp_valh
         movlw   .1
         movwf   dev_no

         clrf    temp5
         swapf   temp2,w
         addwf   temp2,w

         andlw   b'00001111'

         btfsc   dc
         addlw   0x16
         btfsc   dc
         addlw   0x06
         addlw   0x06
         btfss   dc
         addlw   -0x06
         btfsc   temp2,4
         addlw   0x16 - 1 + 0x6
         btfss   dc
         addlw   -0x06
         btfsc   temp2,5
         addlw   0x30
         btfsc   temp2,6
         addlw   0x60
         btfsc   temp2,7
         addlw   0x20
         addlw   0x60
         rlcf     temp5
         btfss   temp5,w
         addlw   -0x60
         movwf   temp7
         btfsc   temp2,7
         incf    temp5
         movf    temp5,w
         addlw   0x30
         movwf   temp5

         swapf   temp7,w       ;separate 10s
         andlw   0x0f
         addlw   0x30         ;convert to ASCII
         movwf   temp6

         movlw   0x0f         ;separate 1s
         andwf   temp7,w
         addlw   0x30         ;convert to ASCII
         movwf   temp7

;copy to message string area
         clrf    string2+3
         clrf    string2+4

         movf    temp5,w
         movwf   string2+0
         movf    temp6,w
         movwf   string2+1
         movf    temp7,w
         movwf   string2+2

;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
;        Convert 16-bit data to 5-digit ASCII
;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=
=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D

;data (100 10 1) to convert is in tmp_valh:tmp_vall

ascii16 nop

 radix dec                    ;base 10

         clrf    ab4dp        ;known zero
         clrf    temp0

         movlw   string3
         movwf   fsr0l

         goto    skpinc1
sub10k   incf    temp0
skpinc1  movlw   10000 & 255
         subwf   tmp_vall

 IFNDEF  kzero

         movlw   10000 >> 8
         skpc
         movlw   (10000>>8)+1
         subwf   tmp_valh
 ELSE
         rlcf     ab4dp,w
         sublw   (10000>>8)+1
         subwf   tmp_valh
 ENDIF
         bc      sub10k
         call    out_temp

         movlw   10
         movwf   temp0
add1K    decf    temp0
         movlw   1000 & 255
         addwf   tmp_vall

 IFNDEF  kzero
         movlw   1000 >> 8
         skpnc
         movlw   (1000>>8)+1
         addwf    tmp_valh
 ELSE
         rlcf     ab4dp,w
         addlw   1000 >> 8
         addwf   tmp_valh
 ENDIF
         bnc     add1k
         call    out_temp

         clrf    temp0
         movlw   100
         goto    skpinc2
sub100
         incf    temp0
skpinc2  subwf   tmp_vall
         skpnc
         goto    sub100

         decf    tmp_valh
         btfss   tmp_valh,7
         goto    sub100

         call    out_temp

         movlw   10
         movwf   temp0
add10a   decf    temp0
         addwf   tmp_vall
         bnc     add10a
         call    out_temp     ;convert and store
         call    out_lo       ;convert and store

 radix hex

         goto    combine      ;add two strings together for message

;convert to ASCII and store

out_temp movf    temp0,w
         addlw   0x30         ;add 0x30 to convert to ASCII
         movwf   indf0
         incf    fsr0l          ;store in RAM
         return

out_lo   movf    tmp_vall,w
         addlw   0x30
         movwf   indf0
         return

;=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D


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