DS2450 conversion read-out

[[mAnNaRo]]

Who know DS2450? I don't understand the A/D conversion values loaded in
the read-out memory page. In 8-bit mode (channel A) the byte loaded is
at address 01 (MSB)...(00(LSB) always H'00')why not 00 (LSB)?
At 9-bit resolution I get value loaded in 00-01 (16bit) addresses but
over 9bit of resolution i.e H'7E90'. Grounded the A/D pin get non zero
values after conversion. Any help?

Alex

 

[Winfield Hill]

[mAnNaRo] Alex wrote...

Who know DS2450? I don't understand the A/D conversion values loaded
in the read-out memory page. In 8-bit mode (channel A) the byte loaded
is at address 01 (MSB)...(00(LSB) always H'00') why not 00 (LSB)?
At 9-bit resolution I get value loaded in 00-01 (16bit) addresses but
over 9bit of resolution i.e H'7E90'. Grounded the A/D pin get non zero
values after conversion. Any help?

That's one complicated A/D. So much so the 24-page datasheet barely
discusses the A-D itself, it's error specs, conversion speed, etc.

 

[Fred Bloggs]

Who know DS2450? I don't understand the A/D conversion values loaded in
the read-out memory page. In 8-bit mode (channel A) the byte loaded is
at address 01 (MSB)...(00(LSB) always H'00')why not 00 (LSB)?
At 9-bit resolution I get value loaded in 00-01 (16bit) addresses but
over 9bit of resolution i.e H'7E90'. Grounded the A/D pin get non zero
values after conversion.

What is there to know- the internal control always left justifies the
conversion result in the two bytes of the memory page assigned to the
particular input channel- be this 2 or 16 bit conversion- and the unused
bits are zero filled. The main complication seems to be the CRC which
includes command+address+data at the end of first page readout and only
data for successive pages - if you request that type of readout.