Heart rate sensor MAX30102

[astanapane]

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.

;-----------------------  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

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:

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:

    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!!!

[richard]

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

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?)

in pbp constants are 16 bit, they are fine in i2c when a 16 bit value is appropriate and the endianness matches
if you use a var there is never any doubt, you get what you asked for but the endianness must match

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

there is no such thing as write address or read address in pbp there is only the address

[astanapane]

there is no such thing as write address or read address in pbp there is only the address

there is an adress of 7 bits....then PBP is taking care for the Read or Write bit.

The following is from the manual of the MAX30102.



But in the program under the registers we are using the AE which is related to write address. Isnt it?

 ADDR = $ae     ; addr is  0x57 << 1

[richard]

But in the program under the registers we are using the AE which is related to write address. Isnt it?

you are trying to create a problem that does not exist there is no such thing as write address or read address in pbp there is only the address
a pbp i2c address is the 7bit manufacturer's address left shifted 1 bit, the only variation is for crappy ancient eeproms where the "page"
address forms part of the address[control] , but bit0 is still under pbp control regardless

you don't quibble the hserout command adding start and stop bits to your serial transmission or even calculating the parity and inserting it also



why should the i2c "high level" commands not be able to set the r/w bit as required, after all that's why you use pbp. it stops you needing to dig into the bowels of i2c transactions

the manual



lets not hear any more of this nonsense

[astanapane]

Thanks Richard,

just wanted to understand it. Now it is clear.

[richard]

now have low pass filtering on pic

73 rpm tonight

[astanapane]

That's really impressed Richard.

Im still working step by step on the code, im still at an early stage.

Just need to understand the methodology.