Heart rate sensor MAX30102

**richard** · - 11th January 2022, 22:11

I followed the manual example: so i wont get consfused.

not really

addr is the i2c device address , reg is the register you are accessing. that example you refer is for an eeprom
where those words make a little sense, in this context they are totally misleading

**astanapane** · - 11th January 2022, 22:40

Originally Posted by richard

not really

addr is the i2c device address , reg is the register you are accessing. that example you refer is for an eeprom
where those words make a little sense, in this context they are totally misleading

once again you are right. I will change the names in the code as well.

One more question. What is the difference on the following?

With the [] and without them. I noticed that i get completely different results. The ones with the [] looks like is the right one as once i place them, i can control the values of the LED's pulse amplidute. Now it is visible the difference.

Code:

addr = $09   ' MODE CONFIGURATION 
i2cwrite  SDA,scl,contwr,addr,[%00000011],error  ' ModLED = $02 as per data sheet heart rate mode, $03 SpO2 mode
pause 10

addr = $0A   ' SpO2 mode configuration 
i2cwrite  SDA,scl,contwr,addr,[%01111101],error  ' check the manual for this configuration
pause 100

addr = $0C    'LED PULSE AMLIDUDE FOR for LED1_PA[7:0] 0x0C
i2cwrite  SDA,scl,Contwr,addr,[$03],error' if LED1_PA = $3F  , 12.6 mA , ($7F is 25.4 mA)
pause 10

addr = $0D    'LED PULSE AMLIDUDE FOR LED2_PA[7:0] 0x0D
i2cwrite  SDA,scl,contwr,addr,[$03],error ' if LED2_PA = $1F , 6.2 mA  , ($7F is 25.4 mA)
pause 10

and the following:

Code:

addr = $09   ' MODE CONFIGURATION 
i2cwrite  SDA,scl,contwr,addr,%00000011,error  ' ModLED = $02 as per data sheet heart rate mode, $03 SpO2 mode
pause 10

addr = $0A   ' SpO2 mode configuration 
i2cwrite  SDA,scl,contwr,addr,%01111101,error  ' check the manual for this configuration
pause 100

addr = $0C    'LED PULSE AMLIDUDE FOR for LED1_PA[7:0] 0x0C
i2cwrite  SDA,scl,Contwr,addr,$03,error' if LED1_PA = $3F  , 12.6 mA , ($7F is 25.4 mA)
pause 10

addr = $0D    'LED PULSE AMLIDUDE FOR LED2_PA[7:0] 0x0D
i2cwrite  SDA,scl,contwr,addr,$03,error ' if LED2_PA = $1F , 6.2 mA  , ($7F is 25.4 mA)
pause 10

**richard** · - 11th January 2022, 22:47

no brackets means no data will be written

**richard** · - 11th January 2022, 22:50

fifo read was stuffed up

reg = FIFO_DATA
i2cread sda,scl,ADDR,reg,[buffer[index+2],buffer[index+1],buffer[index+0],buffer[index+5],buffer[index+4],buffer[index+3]]

the fifo print out is incorrect also , not yet solved

**astanapane** · - 11th January 2022, 23:17

my code , you should know i have no idea :-
1, what led pwr to use
2, what led pwidth to use
3, what sample rate to use
4, what sample resolution to use
5, if there are any fifo overflows and if it matters much
6, what led the readings represents
7, how to interpret the data
8, how much data to collect [i assume at least 2 seconds worth]

most of the drivers i've seen over the net are using the following...

1, what led pwr to use : 0x1F about 6.2 mA
2, what led pwidth to use : 411 which is 18 ADC BIT RESOLUTION based on the manual.
3, what sample rate to use : sample rate per second 100

a configuration should also include: sampleAverage = 8

4, what sample resolution to use :
5, if there are any fifo overflows and if it matters much.
6, what led the readings represents. I will search and find out.
7, how to interpret the data....
8, how much data to collect [i assume at least 2 seconds worth]

**richard** · - 12th January 2022, 02:31

this looks like something, probably needs a lpf and sum of the squares function to remove dc drift

Code:

'****************************************************************'*  Name    : MAX30102  FOR PIC 18 DEMO                         *
'*  Author  :  Richard                                          *
'*  Notice  :                                                   *
'*          :                                                   *
'*  Date    : 9/1/2022                                          *
'*  Version : 1.0                                               *
'*  Notes   : MAX30102                                          *        
'*          :18f26k22 @64Mhz                                    *
'****************************************************************
 
  #CONFIG   ;  The PBP configuration for the PIC18F26K22 is:
    CONFIG FOSC     = INTIO67	       
    CONFIG PLLCFG   = OFF	        ;Oscillator multiplied by 4                       
    CONFIG PRICLKEN  = ON	        ;Primary clock enabled
    CONFIG FCMEN     = OFF	        ;Fail-Safe Clock Monitor disabled
    CONFIG IESO      = OFF	        ;Oscillator Switchover mode disabled
    CONFIG  BOREN    = SBORDIS      ; Brown-out Reset enabled in hardware only (SBOREN is disabled)
    CONFIG  WDTEN    = ON           ; WDT is always enabled. SWDTEN bit has no effect                     ;|
    CONFIG  WDTPS    = 32768        ; 1:32768 ---> HERE enable the watchdog timer with a 1:32768 postscale;|
    CONFIG  PWRTEN   = ON
    CONFIG  HFOFST   = ON           ; HFINTOSC output and ready status are not delayed by the oscillator stable status
    CONFIG  MCLRE    = EXTMCLR      ; MCLR pin enabled, RE3 input pin disabled
    CONFIG  LVP      = OFF          ; Single-Supply ICSP disabled
    CONFIG  XINST    = OFF          ; Instruction set extension and Indexed Addressing mode disabled (Legacy mode)
    CONFIG  DEBUG    = OFF          ; Disabled
    CONFIG  CP0 = OFF             ; Block 0 (000800-003FFFh) not code-protected
    CONFIG  CP1 = OFF             ; Block 1 (004000-007FFFh) not code-protected
    CONFIG  CP2 = OFF             ; Block 2 (008000-00BFFFh) not code-protected
    CONFIG  CP3 = OFF             ; Block 3 (00C000-00FFFFh) not code-protected
    CONFIG  CPB = OFF             ; Boot block (000000-0007FFh) not code-protected
    CONFIG  CPD = OFF             ; Data EEPROM not code-protected
    CONFIG  WRT0 = OFF            ; Block 0 (000800-003FFFh) not write-protected
    CONFIG  WRT1 = OFF            ; Block 1 (004000-007FFFh) not write-protected
    CONFIG  WRT2 = OFF            ; Block 2 (008000-00BFFFh) not write-protected
    CONFIG  WRT3 = OFF            ; Block 3 (00C000-00FFFFh) not write-protected
    CONFIG  WRTC = OFF            ; Configuration registers (300000-3000FFh) not write-protected
    CONFIG  WRTB = OFF            ; Boot Block (000000-0007FFh) not write-protected
    CONFIG  WRTD = OFF            ; Data EEPROM not write-protected
    CONFIG  EBTR0 = OFF           ; Block 0 (000800-003FFFh) not protected from table reads executed in other blocks
    CONFIG  EBTR1 = OFF           ; Block 1 (004000-007FFFh) not protected from table reads executed in other blocks
    CONFIG  EBTR2 = OFF           ; Block 2 (008000-00BFFFh) not protected from table reads executed in other blocks
    CONFIG  EBTR3 = OFF           ; Block 3 (00C000-00FFFFh) not protected from table reads executed in other blocks
    CONFIG  EBTRB = OFF           ; Boot Block (000000-0007FFh) not protected from table reads executed in other blocks
 #ENDCONFIG    
 
  
'define I2C_SLOW 1
define  OSC 64


OSCCON    = %01110000   ; 16Mhz
OSCTUNE.6 = 1           ; Enable 4x PLL


while ! osccon2.7 :WEND ; to make sure the pll has stabilised before you run any other code


   
TRISC = %11011000                  
ANSELC=0


#DEFINE    DEBUGING 1   


#IFNDEF  DEBUGING       
    DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
    DEFINE HSER_TXSTA 24h ' Enable transmit, BRGH = 1
    DEFINE HSER_CLROERR 1 ' Clear overflow automatically
    DEFINE HSER_SPBRG 160 ' 38400 Baud @ 64MHz, -0.08%
    SPBRGH = 1
    BAUDCON.3 = 1         ' Enable 16 bit baudrate generator
#ELSE        
    DEFINE DEBUG_REG PORTB
    DEFINE DEBUG_BIT 7
    DEFINE DEBUG_BAUD 9600
    DEFINE DEBUG_MODE 0
    ANSELB=0
    LATB.7=1
#ENDIF
SDA     var portc.4  ' DATA PIN
SCL     VAR portc.3  ' CLOCK PIN


Timeout    cON 2000
reg        var BYTE
fifo       var byte[6]
addr       var byte 
REVISION   var byte
PARTID     var byte
buffer     var byte[1152]
ptr        var byte
btr        var byte
index      var word
result     var word ext
@result = _fifo 
;-----------------------  REGISTER -------------------------
REG_TEMP_INT         con $1F
REG_TEMP_FRAC        con $20
REG_TEMP_CONFIG      con $21
REG_PART_REVISION    con $FE
REG_MODE             con $09
REG_SPO2_CONFIG      con $0A        ;SPO2_ADC_RGE[6:5]SPO2_SR[4:2]LED_PW[1:0]
REG_LED1_PA          con $0C
REG_LED2_PA          con $0D
FIFO_WR_PTR          con $04        ;FIFO_WR_PTR[4:0]
FIFO_RD_PTR          con $06
FIFO_DATA            con $07
FIFO_CONFIG          con $08        ;FIFO_A_FULL[3:0]   SMP_AVE[7:5]
STATUS1              con 0          ;A_FULL[7]


' -----------------------------------------------------------------------------|  


#IFDEF  DEBUGING
    PAUSE 2000
    DEBUG 13,10,  "READY"
#ENDIF
    ADDR = $ae     ; addr is  0x57 << 1
    reg = REG_PART_REVISION
    i2cread  SDA,scl,ADDR,reg,[REVISION,PARTID]
    reg = REG_MODE 
    i2cwrite  SDA,scl,ADDR,reg,[3] 
    reg = REG_SPO2_CONFIG
    i2cwrite  SDA,scl,ADDR,reg,[$20]
    reg = REG_LED2_PA 
    i2cwrite  SDA,scl,ADDR,reg,[9]
    reg = REG_LED1_PA 
    i2cwrite  SDA,scl,ADDR,reg,[9]
    reg = FIFO_CONFIG  
    i2cwrite  SDA,scl,ADDR,reg,[16]        
    
#IFNDEF  DEBUGING
    HSEROUT [$73,$03,$04,$11,$ff,$ff,"PART ID: 0X",hex PARTID,"/0X", hex REVISION,$00]
    Hserin  timeout,error,[wait(6)]
#ELSE
    DEBUG 13,10,  "PART ID: 0X",hex PARTID,"/0X",hex REVISION
#ENDIF 


'********************************************************************************
start:
    reg= REG_TEMP_CONFIG
    i2cwrite  SDA,scl,ADDR,reg,[1] 
    reg= REG_TEMP_INT        
    i2cread  sda,scl,ADDR,reg,[fifo[0],fifo[1]]
#IFNDEF  DEBUGING
    HSEROUT [$73,$05,$0A,$11,$07,$E0,"TEMP: ",DEC fifo[0],".",DEC2( fifo[1]<<6),$00]  
    Hserin  timeout,error,[wait(6)]
#ELSE
    DEBUG 13,10, "TEMP: ",DEC fifo[0],".",DEC2( fifo[1]<<6) 
#ENDIF
    GOSUB AQUIRE
    pause 5000
goto start


aquire:
    reg= FIFO_WR_PTR
    i2cwrite  SDA,scl,ADDR,reg,[0]
    reg= FIFO_RD_PTR
    i2cwrite  SDA,scl,ADDR,reg,[0]
    pause 200 
 FOR index = 0 TO 1151 STEP 0
    
    btr = 0
    reg = STATUS1
    WHILE btr&$80 = 0
    i2cread  sda,scl,ADDR,reg,[btr]
    WEND      
    
    reg = FIFO_RD_PTR
    i2cread  SDA,scl,ADDR,reg,[btr]
    btr = (btr - ptr) &  31
    WHILE btr
    reg = FIFO_DATA         
    i2cread  sda,scl,ADDR,reg,[buffer[index + 2],buffer[index + 1],buffer[index + 0],buffer[index + 5],buffer[index + 4],buffer[index + 3]]
    index = index + 6
    btr = btr - 1
    ptr = (Ptr + 1) &  31
    WEND
     pause 200 
    DEBUG "."
 NEXT  
    FOR index = 0 TO 1151 STEP 0
    for ptr = 0 to 2
    fifo[ptr] = buffer[index + ptr]
    next
    DEBUG 13,10;,  hex2 fifo[2] , hex2 fifo[1],  hex2 fifo[0]
'    asm         ;ROTATE READING TO GET SUFFICIENT RESOLOUTION INTO UPPER WORD
'    banksel _fifo 
'    bcf STATUS,C
'    RRCF  _fifo + 2 ,f
'    RRCF  _fifo + 1 ,f
'    RRCF  _fifo    ,f
'    bcf STATUS,C
'    RRCF  _fifo + 2 ,f
'    RRCF  _fifo + 1 ,f
'    RRCF  _fifo    ,f
'    banksel 0
'    endasm
    DEBUG 9,HEX4 result 
    index = index + 3
'    DEBUG 13,10, hex2 buffer[index+2],hex2 buffer[index+1],hex2 buffer[index],9 ,HEX4 result  
'    DEBUG 9,  hex2 fifo[2] , hex2 fifo[1],  hex2 fifo[0]
    for ptr = 0 to 2
    fifo[ptr] = buffer[index + ptr]
    next
    
'    DEBUG 9,  hex2 fifo[2] , hex2 fifo[1],  hex2 fifo[0]
'    asm         ;ROTATE READING TO GET SUFFICIENT RESOLOUTION INTO UPPER WORD 
'    banksel _fifo
'    bcf STATUS,C
'    RRCF  _fifo +2 ,f
'    RRCF  _fifo +1 ,f
'    RRCF  _fifo    ,f
'    bcf STATUS,C
'    RRCF  _fifo +2 ,f
'    RRCF  _fifo +1 ,f
'    RRCF  _fifo    ,f
'    banksel 0
'    endasm
    DEBUG 9,HEX4 result
    index = index + 3
   NEXT 
RETURN

**richard** · - 12th January 2022, 08:38

its alive i think
Name: hb.jpg
Views: 5200
Size: 192.7 KB

gives me a 63 rpm

**astanapane** · - 12th January 2022, 11:07

Richard,

looking at your code,i'm learning lots of things.

All the registers you have are constants. And that is what i've thought also in the beggining.

Code:

;-----------------------  REGISTER -------------------------
REG_TEMP_INT         con $1F
REG_TEMP_FRAC        con $20
REG_TEMP_CONFIG      con $21
REG_PART_REVISION    con $FE
REG_MODE             con $09
REG_SPO2_CONFIG      con $0A        ;SPO2_ADC_RGE[6:5]SPO2_SR[4:2]LED_PW[1:0]
REG_LED1_PA          con $0C
REG_LED2_PA          con $0D
FIFO_WR_PTR          con $04        ;FIFO_WR_PTR[4:0]
FIFO_RD_PTR          con $06
FIFO_DATA            con $07
FIFO_CONFIG          con $08        ;FIFO_A_FULL[3:0]   SMP_AVE[7:5]
STATUS1              con 0          ;A_FULL[7]


' -----------------------------------------------------------------------------|

But in the manual it says that we never use constants for the I2C command.

What i have realised is that you refer to the

Code:

reg var byte

everytime you need to asign a constant value to it. Is that right? with that way we alter the restriction of using constants. (or am i wrong?)

Sencod question.

I see you are always using the Write Address:

Code:

ADDR = $ae     ; addr is  0x57 << 1
    reg = REG_PART_REVISION
    i2cread  SDA,scl,ADDR,reg,[REVISION,PARTID]
    reg = REG_MODE 
    i2cwrite  SDA,scl,ADDR,reg,[3] 
    reg = REG_SPO2_CONFIG
    i2cwrite  SDA,scl,ADDR,reg,[$20]
    reg = REG_LED2_PA 
    i2cwrite  SDA,scl,ADDR,reg,[9]
    reg = REG_LED1_PA 
    i2cwrite  SDA,scl,ADDR,reg,[9]
    reg = FIFO_CONFIG  
    i2cwrite  SDA,scl,ADDR,reg,[16]

even if you want to read from:

Code:

    reg= REG_TEMP_INT        
    i2cread  sda,scl,ADDR,reg,[fifo[0],fifo[1]]

im confused here. When do we use the write address and when do we use the read address!!!

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