Fram temperature logger

[richard]

i knocked up this simple example to test a few ideas on fram algorithms while waiting for my pcbs to to arrive. it reads the temp every 30 seconds and once every 6 minutes logs it to a circular buffer in fram with 256 elements of depth. that just over 24 hours worth, the head and tail are also stored in fram so it can resume where it left off when interrupted.
the as6221 temp sensor is the bees knees of temperature sensors , super accurate and no detectable self heating at all

'****************************************************************
'*  Name    : FRAM.BAS                                          *
'*  Author  : richard                                           *
'*  Notice  : Copyright (c) 2022 caveat emptor                  *
'*          : All Rights Reserved                               *
'*  Date    : 23/09/2022                                        *
'*  Version : 1.0                                               *
'*  Notes   :  as6221 + MB85RC256V 24HR TEMPERATURE DATA LOGGER *
'*          :  256 BYTE CIRCULAR BUFFER IN FRAM  PIC12F1822     *
'****************************************************************
#CONFIG
  __config _CONFIG1, _FOSC_INTOSC & _WDTE_OFF & _PWRTE_ON & _MCLRE_ON & _CP_OFF & _CPD_OFF & _BOREN_ON & _CLKOUTEN_OFF & _IESO_ON & _FCMEN_ON
  __config _CONFIG2, _WRT_OFF & _PLLEN_ON & _STVREN_ON & _BORV_19 & _LVP_OFF
#ENDCONFIG


DEFINE INTHAND   disp
DEFINE I2C_SLOW 1    ; for high speed osc
DEFINE I2C_HOLD 1    ; chip employs clock stretching


    as6221_ADDRESS CON 144
    fram__ADDRESS  CON 160
    
    OSCCON  = $70
    DEFINE OSC 32


    LATA.0 = 1            ;debug
    trisa = %11111111     ;debug 
    ANSELA = 0 
    
    RCSTA = $90   ' Enable serial port & continuous receive
    TXSTA = $24   ' Enable transmit, BRGH = 1
    SPBRG = 64    ' 9600 Baud @ 32MHz, 0.04%
    SPBRGH = 3
    BAUDCON.3 = 1 ' Enable 16 bit baudrate generator
    'SEND C  TO CLEAR P TP PRINTOUT
    


    clear
    
    PAUSE 2000
    hserout [ "READY" ]
    
    SDA VAR PORTA.5
    SCK VAR PORTA.4
    timer1_reload con  45537  '10mS
    
    millies   var word      BANK0
    rxbuff    VAR BYTE[6]   BANK0  ;5 CHR + NULL
    rxinx     VAR BYTE      BANK0 
    rxflg     VAR BYTE      BANK0   
    NOW       VAR WORD
    dTIME     VAR WORD
    readtime  VAR WORD
    REG       VAR BYTE
    Temp      var word 
    dc        var word
    head_fs   VAR BYTE    ;fram shadow var
    tail_fs   VAR BYTE    ;fram shadow var
    rd_ptr    VAR BYTE
    inx       var word 


    ;fram addr pointers
    fram_ptr_t con $100    ;to temperature data store
    fram_ptr_v con 0       ;to variable data  store
    head       con 0       ;head_fs
    tail       con 4       ;tail_fs 


    inx = RCREG   ;DUMMY READ CLR RCIF
    T1CON   = $21 
    PIR1    = 0   
    intcon  = $C0      
    pie1.0  = 1
    PIE1.5  = 1
    
    ;init  fram
    inx = fram_ptr_v
    I2CREAD  SDA,SCK,fram__ADDRESS,inx + head,[head_fs]
    I2CREAD  SDA,SCK,fram__ADDRESS,inx + tail,[tail_fs]
    hserout [ 13,10,"init H/T ",dec head_fs,"/",dec tail_fs]    
main:
    GOSUB GET_NOW 
    if ((NOW-readTIME)>3000) then    '30 sec   ie 3000*10Ms 
        GOSUB GET_tmp
        readTIME = now
    endif
    if ((NOW-dTIME )>36000) then     '6 min LOG READING
        GOSUB FWR_tmp 
        dTIME = now
    endif
    if rxflg then    'SEND C TO CLEAR P TO PRINTOUT WITH A CR [/R] TERMINATION
        hserout [13,10, str rxbuff,13,10 ]
        IF  rxbuff[0]== "C" THEN
            head_fs=tail_fs
            I2cwrite  SDA,SCK,fram__ADDRESS,inx + head,[head_fs]
        ELSEIF rxbuff[0]== "P" THEN   
            GOSUB fram_read_t
        endif
        rxflg=0
        rxinx=0 
    endif
goto main   
    
GET_NOW:   ;millies x 10
    pie1.0 = 0
    NOW = MILLIES   ;millies x 10mS
    pie1.0 = 1
RETURN


GET_tmp:    ;READ AND PRINT TEMPERATURE H/T
    REG =  0
    I2CREAD  SDA,SCK,as6221_ADDRESS,REG,[temp.highbyte,temp.lowbyte];
    dc = temp*100
    dc = div32 128
    hserout [ 13,10,"temp c#",9,dec dc/100,".",dec2 dc//100,9,dec head_fs,9,dec tail_fs ] 
return 


FWR_tmp:      ;WRITE "temp" TO BUFFER @HEAD 
    I2cwrite  SDA,SCK, fram__ADDRESS,fram_ptr_t + head_fs*2 ,[dc]
    head_fs = head_fs+1
    inx = fram_ptr_v
    I2cwrite  SDA,SCK,fram__ADDRESS,inx + head,[head_fs]
    if head_fs=tail_fs then 
        tail_fs = tail_fs + 1 ;CIRCLE ovrflw
        I2cwrite  SDA,SCK,fram__ADDRESS,inx + tail,[tail_fs]
    endif
return


fram_read_t:  'PRINTOUT  BUFFER
    inx = fram_ptr_v
    I2CREAD  SDA,SCK,fram__ADDRESS,inx + tail,[rd_ptr]
    hserout [ 13,10,"DATA :-",13,10]
    while (head_fs-rd_ptr)
       I2CREAD  SDA,SCK, fram__ADDRESS, fram_ptr_t + rd_ptr*2,[dc]
       hserout [ 13,10,dec3 rd_ptr," temp",9,dec dc/100,".",dec2 dc//100 ]
       rd_ptr = rd_ptr + 1
    wend
return 
       
asm
disp
    BANKSEL 0
    BTFSS PIR1,5     ;RXISR
    goto t01         ;NEXT ISR
    BTFSC _rxflg ,0  ;BUFF full
    GOTO SFT
    movlw high(_rxbuff+1)
    movwf FSR0H
    movlw LOW(_rxbuff)
    movwf FSR0L
    MOVF _rxinx,W
    ADDWF  FSR0L ,F
    INCF   _rxinx,F
    movlw 6          ;BUFF SIZE
    SUBWF  _rxinx,W  ;full UP ?
    BTFSS STATUS ,Z
    GOTO NB
    CLRF   _rxinx    ;ROLL OVER
SF  
    INCF FSR0L,F 
    CLRF INDF0      ;NULL TERMINATE
    BANKSEL 0
    BSF  _rxflg,0    ;full UP / SET FLAG
SFT 
    BANKSEL RCREG
    MOVF RCREG,W     ;JUST CLR FLG
    GOTO t01         ;NEXT ISR TO SERVICE
NB  
    BANKSEL RCREG
    MOVF RCREG,W
    MOVWF  INDF0     ;SAVE CHR
    movlw 13         ;TERMINATE ON '/r'
    SUBWF   INDF0,W
    BTFSC STATUS ,Z
    GOTO SF          ;SET FLAG
    ;GOTO disp       ;RECHECK FIFO
t01     ;tmr1 isr 
    BANKSEL 0
    BTFSS PIR1 ,0
    goto ex
    BCF  T1CON,0     ;stop timer
    MOVLW HIGH (_timer1_reload)
    ADDWF TMR1H,F
    MOVLW LOW (_timer1_reload) ;Add TimerReload to the_ 
    ADDWF TMR1L,F              ; value in Timer1
    BTFSC STATUS,C
    INCF  TMR1H,F
    BSF  T1CON,0      ;START timer
    BCF PIR1   ,0 
    MOVLW 1
    ADDWF _millies,F
    BTFSC STATUS,C
    INCF  _millies+1,F
ex      
    RETFIE   
endasm

printout

READY
init H/T 156/132
temp c# 22.63 156 132
temp c# 22.60 156 132
P


DATA :-

132 temp 22.91
133 temp 22.91
134 temp 22.90
135 temp 22.96
136 temp 22.98
137 temp 23.10
138 temp 23.05
139 temp 22.67
140 temp 22.54
141 temp 22.46
142 temp 22.38
143 temp 22.26
144 temp 22.26
145 temp 22.73
146 temp 22.77
147 temp 22.83
148 temp 22.73
149 temp 22.71
150 temp 22.81
151 temp 22.76
152 temp 22.74
153 temp 22.57
154 temp 22.66
155 temp 22.67

[Ioannis]

Nice chip this AS6221. But how on earth can one solder this tiny little chip?

I think this line:

hserout [ 13,10,"temp c#",9,dec dc/100,".",dec2 dc//100,9,dec head_fs,9,dec tail_fs ]

can be

hserout [ 13,10,"temp c#",9,dec dc/100,".",dec2 dc,9,dec head_fs,9,dec tail_fs ]

The dc variable holds the temp in x1000, right? So printing the last 2 digit with DEC2 does not need //100.

Ioannis

[richard]

Nice chip this AS6221. But how on earth can one solder this tiny little chip?

i can't i can barely see it. used a dev board , their not cheap either.
when i first saw the board i thought they had sent me a blank board the smd resistors and caps are grains of sand
or dust specs

The dc variable holds the temp in x1000, right? So printing the last 2 digit with DEC2 does not need //100.

no its temp x100 and the second term is the remainder {modulus) I'm not confidant that a simple division would ever be correct

[Ioannis]

no its temp x100 and the second term is the remainder {modulus) I'm not confidant that a simple division would ever be correct

I am not sure I follow.

dc var as I understand, holds the value say, 2236. This represents the value 22.36 degrees celcious.

To display it as integer, dc/100 is used and for the floating part, DEC2 dc will display the least significant digits, that is 36. So the use of //100 I think, only increases the code size.

Ioannis

[richard]

DEC2 dc will display the least significant digits

and it does , that's another one of those things i have micro managed forever for no good reason
duly noted thanks