Hi jamr,

have you checked the user manual UM10116?

I havn't used ADC with the LPC936 yet. But if I understood the description
of "Table 18: A/D Mode register B (ADMODB - address A1h) bit description" on
pages 35/36 correctly, it's not possible to use ADC and DAC of one block at
the same time.
Look at bits 2 (ENDAC0) an 3 (ENDAC1).

regards

Armin

-----Ursprüngliche Nachricht-----
Von: l...@yahoogroups.com [mailto:l...@yahoogroups.com]Im
Auftrag von Juan Antonio
Gesendet: Montag, 5. Januar 2009 16:03
An: l...@yahoogroups.com
Betreff: [lpc900_users]
sorry,i redo the mail, I believe that the information was a little useless.

I´m currently working in a development for a hand-portable system, using
features of the LPC family ( low power, low consumption ).
I´m using LPC936 (2 AD modules-4 channels with shared controls).

I do a little programm in assembler and I use DAC1(AD13) only in AD1
module, and it’s OK.
But when I want to use AD00 + DAC0(AD03) in AD0 module I have an incorrect
function: if I read AD00, DAC0(AD03) disappears.

I think is a problem manipulating the shared control registers.
There are 4 channels in AD0 module, and I assume that is possible to work
with AD00 + DAC0(AD03) at same time.
Where could I find more information about this issue??
Can someone help me???

" For a prompt reply I would be very thankful ".
gracias a todos.
jamr

------------------------------------



(You need to be a member of LPC900_users -- send a blank email to LPC900_users-subscribe@yahoogroups.com )

--- In l...@yahoogroups.com, "ast66" wrote:
>
> Hi jamr,
>=20
> have you checked the user manual UM10116?
>=20
> I havn't used ADC with the LPC936 yet. But if I understood the
description
> of "Table 18: A/D Mode register B (ADMODB - address A1h) bit
description" on
> pages 35/36 correctly, it's not possible to use ADC and DAC of one
block at
> the same time.
> Look at bits 2 (ENDAC0) an 3 (ENDAC1).
>=20
> regards
>=20
> Armin
>=20
> -----Urspr=FCngliche Nachricht-----
> Von: l...@yahoogroups.com
[mailto:l...@yahoogroups.com]Im
> Auftrag von Juan Antonio
> Gesendet: Montag, 5. Januar 2009 16:03
> An: l...@yahoogroups.com
> Betreff: [lpc900_users]
>=20
>=20
> sorry,i redo the mail, I believe that the information was a little
useless.
>=20
> I=B4m currently working in a development for a hand-portable system, usin=
g
> features of the LPC family ( low power, low consumption ).
> I=B4m using LPC936 (2 AD modules-4 channels with shared controls).
>=20
> I do a little programm in assembler and I use DAC1(AD13) only in AD1
> module, and it's OK.
> But when I want to use AD00 + DAC0(AD03) in AD0 module I have an
incorrect
> function: if I read AD00, DAC0(AD03) disappears.
>=20
> I think is a problem manipulating the shared control registers.
> There are 4 channels in AD0 module, and I assume that is possible to
work
> with AD00 + DAC0(AD03) at same time.
> Where could I find more information about this issue??
> Can someone help me???
>=20
> " For a prompt reply I would be very thankful ".
> gracias a todos.
> jamr
>
You can not use the ADC and the DAC of one block simultaneously. In
theory you can use a capacitor to buffer the output of the DAC. It
needs to be big enough to keep the voltage for the time you use the
block as ADC but small enough to be charged fast enough to support
your max frequency. Hope you understand what I am telling you. If not,
my only recommendation is to NOT use the block with both functions in
one system.=20

Bob
------------------------------------

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