Port Addressing Issue

[CocaColaKid]

This code works great for reading 5 sensors however I want to decrease the amount of time it takes to run through this subroutine by not trying to read a sensor if its not being used. My problem starts with the line "if sensor = 1 then" because it thinks I'm trying to compare the value stored in sensor which is not what I want it to do. I need it to compare the port associated with the number against a specific value. Any ideas on how to resolve this issue?

read_sensors:
    for sensor = 0 to 4
    temp_c = 0
    temp_f = 0
    temp_k = 0
    dummy = 0
    dq = 0
    gosub ds_init
    gosub read_temp
    sign_c_array[sensor] = sign_c
    sign_f_array[sensor] = sign_f
    temp_c_array[sensor] = temp_c
    temp_f_array[sensor] = temp_f
    temp_k_array[sensor] = temp_k
    next sensor

ds_init:
    low sensor                              ' Set the data pin low to initialize
    pauseus 500                             ' Wait for more than 480us
    input sensor                            ' Make data pin port an input
    pauseus 100                             ' Wait for more than 60us
    if sensor = 1 then                      ' Is there a DS18B20 detected
        debug cmd,line3,"Not Present"       ' If not set flag indicating so
        SensorMissing = 1
        return					
    endif					
    pauseus 400                             ' Wait for end of presence pulse
    debug cmd,line3,"Present    "           ' Set flag indicating there is a 
    SensorMissing = 0                       ' sensor present
    return

read_temp:
       if SensorMissing = 1 then            ' If the sensor is not present load
            temp_c = 32767                  ' these values in place of the 
            temp_f = 62181                  ' temperature indicating there is
            temp_k = 60082                  ' a problem with the sensor
            sign_c = "+"
            sign_f = "+"
            return
        endif
        owout sensor,1,[$CC,$44]            ' Send start temperature conversion 
                                            ' command
        low portb.5                         ' Turn on transistor between rail and 
                                            ' data pin
        pause 750                           ' Allow enough time to process Tconv
        high portb.5                        ' Turn off transistor between rail and 
                                            ' data pin
        owout sensor,1,[$CC,$BE]            ' Send read scratch pad command
        owin sensor,0,[STR dq\9]            ' Read all 9 bytes and store them in dq 
                                            ' array
        raw_temp.Byte0 = dq[0]              ' Isolate raw temperature from the rest
        raw_temp.Byte1 = dq[1]
        gosub get_crc                       ' Calculate the CRC of the data
        gosub convert_temp                  ' Convert raw data into real temps
        return

[rhino]

read_sensors:
for sensor = 0 to 4

Can you use a different variable name here? Just a quick thought.

[CocaColaKid]

The variable name will not matter. What I need to be is be able to step through portb.0 to portb.4 which works fine just using 0 to 4. The problem is that when "sensor" is equal to 0 the if then statement thinks that sensor is 0 and not 1 even though the port is being pulled high. As such when I do it for 2,3 and 4 the same thing. It looks at the number and not the state of the port.

[rhino]

I see... don't think my code analogy will work, but what you are after is reading the state of the "portB.sensor" input, where sensor is the bit #... right?

[CocaColaKid]

Bingo! That is exactly what I want

[hmr]

Hi Cocacolakid

Try this:

PortB.0 [sensor]

If you need more info, read section 4.11 on the manual.

Hope this help.

Hans

[CocaColaKid]

After sleeping on this I figured out an easy way to accomplish this task. I just added a subroutine that gets the port state according to the value of "sensor". I works like a charm.

read_sensors:
    for sensor = 0 to 4
    temp_c = 0
    temp_f = 0
    temp_k = 0
    dummy = 0
    dq = 0
    gosub ds_init
    gosub read_temp
    sign_c_array[sensor] = sign_c
    sign_f_array[sensor] = sign_f
    temp_c_array[sensor] = temp_c
    temp_f_array[sensor] = temp_f
    temp_k_array[sensor] = temp_k
    next sensor

ds_init:
    low sensor                              ' Set the data pin low to initialize
    pauseus 500                             ' Wait for more than 480us
    input sensor                            ' Make data pin port an input
    pauseus 100                             ' Wait for more than 60us
    gosub direction
    if SensorState = 1 then                ' Is there a DS18B20 detected
        debug cmd,line3,"Not Present"       ' If not set flag indicating so
        SensorMissing = 1
        return					
    endif					
    pauseus 400                             ' Wait for end of presence pulse
    debug cmd,line3,"Present    "           ' Set flag indicating there is a 
    SensorMissing = 0                       ' sensor present
    return

direction:
    if sensor = 0 then 
    SensorState = portb.0
    return
    endif
    if sensor = 1 then 
    SensorState = portb.1
    return
    endif
    if sensor = 2 then 
    SensorState = portb.2
    return
    endif
    if sensor = 3 then 
    SensorState = portb.3
    return
    endif
    if sensor = 4 then 
    SensorState = portb.4
    return
    endif

read_temp:
    if SensorMissing = 1 then
            temp_c = 32767
            temp_f = 62181
            temp_k = 60082
            sign_c = "+"
            sign_f = "+"
            return
        endif
        owout sensor,1,[$CC,$44]            ' Send start temperature conversion 
                                            ' command
        low portb.5                         ' Turn on transistor between rail and 
                                            ' data pin
        pause 750                           ' Allow enough time to process Tconv
        high portb.5                        ' Turn off transistor between rail and 
                                            ' data pin
        owout sensor,1,[$CC,$BE]            ' Send read scratch pad command
        owin sensor,0,[STR dq\9]            ' Read all 9 bytes and store them in dq 
                                            ' array
        raw_temp.Byte0 = dq[0]              ' Isolate raw temperature from the rest
        raw_temp.Byte1 = dq[1]
        gosub get_crc                       ' Calculate the CRC of the data
        gosub convert_temp                  ' Convert raw data into real temps
        return

[rhino]

Glad to see you found a solution. I still think there should be a way to do it similar to what I was thinking, and Hans's idea. Any thoughts from the guru's?