ADC xttiny

SZTRAD · Joined: 30 Dec 2019 Posts: 165

Greetings to all
I may have missed something, but how do I set the reference voltage for xttina? Of course it works with ASM, but according to the help there should be a config vref configuration. I didn't find a description for her.
The MUX directive is not clear to me in the ADC configuration. I understood correctly that if I don't use it, I can load any channel, but if I use it, only the value of this channel will be returned to the getadc function?

Regards

(BASCOM-AVR version : 2.0.8.3 )

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

you can use CONFIG VREF. For example : config vref=on,adc=1v1,dac=1v1
use CTRL+SPACE to get the values.

I see it is missing from the help. Once i added i will share it here.

for the mux :

Mux position. This bit field selects which single-ended analog input is connected to the ADC. If these bits are changed during a conversion, the change will not take effect until this conversion is complete.
Possible values :
- GND : 0V, GND
- TEMPSENSE : Temperature sensor
- INTREF : Internal reference (from VREF)
- DAC0 : DAC0 output
0-11 : ADC input pin 0-11

this means that the mux selects the input. if you use a number you can select any input. between 0-11 you select the adc inputs. Or you can load &H1F to select GND.
But GND will load the value &H1F , and is more clear.
When you want to change the number dynamic you just assign the ADC0_MUXPOS register with the channel value.

SZTRAD · Joined: 30 Dec 2019 Posts: 165

Thank you
It didn't occur to me to write like that

I forgot to ask. When asking for temperature, does the reference voltage switch automatically or should I watch it?

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

SZTRAD · Joined: 30 Dec 2019 Posts: 165

thank you for answer
I probably wrote it wrong.
Let's take a model example. I need to measure the temperature during the program. I have a reference set to measure voltage at 2.5V. I will recalculate the reference to 1.1V and read the result for MUXPOS 1E hex (here it is interesting because the microchip does not indicate this position in 1604, but in ADC it states that temperature measurement is present). I subtract the offset from the result and multiply by the gain and I should have the chip temperature. Then I return the settings to the state I need for normal system operation. This was my point if it was done automatically (with the config set to MUX = TEMPSENSE) or I have to take care of it myself. Because of the speed, I also have to adjust other parameters of the ADC conversion, which should be given by the catalog sheet for temperature measurement.
Regards RS

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

all i know is that reading the temp sensor must use 1v1. and the PDF says to set the ref to 1v1. So it will not do that automatic.
But of course you could try it.
The docs are however not really consistent. as i worked my way through all of them i found that it does not always match the atd/inc file form microchip. so some times it is unsure if a device is present or not.
the temp reference is also not consistent between all docs. i did try the internal ref and that worked. the dac also works as do the normal inputs.
the temp sensor result i can not understand. i read 532. the offset is -117 and the gain 148. i get that the result is in Kelvin but when i convert to Celsius i get impossible values.

in the dat file the prodsig_address value is not correct. it must be :
prodsig_address=$1100

Then it will match the value from the normal IO registers.
I will have a look at it later when i have different chips. it is possible the temp. sensor is simply not working.
I would be interested in your values.

SZTRAD · Joined: 30 Dec 2019 Posts: 165

I'm a lot confused.
When I look at atmelstudio, prodsig_address is 1103 for chips, for example 1604.06 and 816

<memory-segment exec="0" name="EEPROM" pagesize="0x20" rw="RW" size="0x0080" start="0x00001400" type="eeprom"/>
<memory-segment exec="0" name="FUSES" pagesize="0x20" rw="RW" size="0xA" start="0x00001280" type="fuses"/>
<memory-segment exec="0" name="INTERNAL_SRAM" rw="RW" size="0x0200" start="0x3e00" type="ram"/>
<memory-segment exec="0" name="IO" rw="RW" size="0x1100" start="0x00000000" type="io"/>
<memory-segment exec="0" name="LOCKBITS" pagesize="0x20" rw="RW" size="0x1" start="0x0000128A" type="lockbits"/>
<memory-segment exec="0" name="MAPPED_PROGMEM" pagesize="0x40" rw="RW" size="0x2000" start="0x00008000" type="other"/>
<memory-segment exec="0" name="PROD_SIGNATURES" pagesize="0x40" rw="R" size="0x3D" start="0x00001103" type="signatures"/>
<memory-segment exec="0" name="SIGNATURES" pagesize="0x40" rw="R" size="0x3" start="0x00001100" type="signatures"/>
<memory-segment exec="0" name="USER_SIGNATURES" pagesize="0x20" rw="RW" size="0x20" start="0x00001300" type="user_signatures"/>

At 1606 in the catalog sheet they write that it does not have a sensor but it is listed in the AS
<value-group caption="Analog Channel Selection Bits select" name="ADC_MUXPOS">
<value caption="ADC input pin 0" name="AIN0" value="0x00"/>
<value caption="ADC input pin 1" name="AIN1" value="0x01"/>
<value caption="ADC input pin 2" name="AIN2" value="0x02"/>
<value caption="ADC input pin 3" name="AIN3" value="0x03"/>
<value caption="ADC input pin 4" name="AIN4" value="0x04"/>
<value caption="ADC input pin 5" name="AIN5" value="0x05"/>
<value caption="ADC input pin 6" name="AIN6" value="0x06"/>
<value caption="ADC input pin 7" name="AIN7" value="0x07"/>
<value caption="ADC input pin 8" name="AIN8" value="0x08"/>
<value caption="ADC input pin 9" name="AIN9" value="0x09"/>
<value caption="ADC input pin 10" name="AIN10" value="0x0A"/>
<value caption="ADC input pin 11" name="AIN11" value="0x0B"/>
<value caption="Internal Ref" name="INTREF" value="0x1D"/>
<value caption="Temp sensor/DAC1" name="TEMPSENSE" value="0x1E"/>
<value caption="GND" name="GND" value="0x1F"/>

At 1606 in the catalog sheet they write that it does not have a sensor but it is listed in the AS
If I read the values from prodsig_address 1103, the offset is 2 and the gain is 11
If you read the values from prodsig_address 1100, the offset is 255 and the gain is 30
The value from the position 1E converter is 90
In both cases, temperature is nonsense.
Your value already looks more believable at 51 ° C for the case you wrote.
Well, I'll try to explore it through C in my spare time.
Regards RS

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

It is indeed confusing.
The prodsig_address must be changed to :$1100 in the dat files.
I already did that for the next update. At the moment it is 1103
that is technically ok but the ID fuses are located at 1100.

When you change the dat file the fuses will give the right value.
Of course you can also read the registers directly. They always show the right value.
Some pdf are preliminary. I could not find definitive ones for all processors.
Also because i started long time ago, some chips were moved from one sheet to the other.
There are some errata sheets too.
The inc files are also a mystery as they some times contain info about hardware that is not available. i guess it is not up to date yet. I did inform microchip support.
The last update i downloaded had better files. the xml/atdf and inc files are distilled from production. so i do not get why they are not correct. but maybe it is because they samples/experimented.
Or some things are not correct in the sheets yet.
Anyway, i use both the atdf and the inc files to create the DAT files. Of course i also add some things. And sometimes i remove/remark some stuff when it really does not make sense.
I did not even write code for the temp, i only measured the value. And then i checked in excel to see what Kelvin i got and what it meant in Celsius. I only have tiny816 for test.
I do recall that it worked ok on xmega. I spend some time at it, that is when i found the prodsig_address problem. But even with that i found no solution. Maybe in the future this will be discovered.

SZTRAD · Joined: 30 Dec 2019 Posts: 165

We'll see
By the way, one of the reasons why I used to reach for AVR after 8051 and not PIC were catalog sheets. The microchip has always been confused.
Otherwise, I modified the DAT files, but the results written to me by the programmer seemed strange to me.
I'll try it from their AS and see what kind of data it spills.

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

yes the datasheets are very important. atmel did a great job. support was also great.
with microchip the docs are still complete for AVR. Only this new series seem to have some confusing things. but they probably also use copy, paste & edit. and then forget some editing. this happens to me too Embarassed

only support seems bad. it seems there is only 1 person working there. when they are away for a week you dont get a reply. and getting samples is a drama. for some reason i can not order samples from my country. but of course there is farnell which always deliver on time.
Even 20 years ago i asked atmel to have some sort of subscription service where you can get printed data sheets and/or sample chips. and a paid service, i do not mind to pay. but just like atmel, microchip only wants to sell chips. the software and the rest they probably see as a necessary evil.

SZTRAD · Joined: 30 Dec 2019 Posts: 165

So I tried differently and unfortunately I have to say that it works for them. I'll have to explore Bascom and the features in the data entry file. This is an extract from Arduino's place setting and it works for 1604. It oscillates a bit, but it can be smoothed out.

arduino code in the txt file

Extract from the terminal
Sigrow tempsense1: -1
Sigrow tempsense1 HEX: FFFFFFFF
Sigrow tempsense0: 146
Sigrow tempsense0 HEX: 92
524
525
76650
System temperature is: 25 C

I don't understand tempsense1 and value a bit. Excerpt from the programmer in the picture.

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

I see what i did wrong : int8_t sigrow_offset = SIGROW.TEMPSENSE1; // Read signed value from signature row
it is a signed short int. now i get the proper result too. Very Happy

thanks

albertsm · Joined: 09 Apr 2004 Posts: 5921 Location: Holland

i added a simple option to read the temp in Kelvin