max 1270
Dear all,
At the monent I am working on a small project with uses an AD Converter MAX1270.
I have found different programs and schematic for this, but till now i was not able to get it working
If i look on the makers instruction i find a different layout than other on this forum
Can somebody indicates where i can find a (working) schema for the Max1270 with an bsxII
your assistance is highly appriciated
Regards
Huib
·
At the monent I am working on a small project with uses an AD Converter MAX1270.
I have found different programs and schematic for this, but till now i was not able to get it working
If i look on the makers instruction i find a different layout than other on this forum
Can somebody indicates where i can find a (working) schema for the Max1270 with an bsxII
your assistance is highly appriciated
Regards
Huib
·
Comments
A·"bsxII"?· Is that a Parallax product or some knock-off?
Provide details.
It should have been BS2sx instead
however the question remains the same;
on certain schematic is mentioned that:
a) vdd / shdn to ground two (0.1 uF and 10 uF)
ref to ground one 4.7 uF
refadj to ground 0.1uF
b) vdd / shdn to ground one capacitor (0.1 uF)
ref to ground one 4.7 uF
refadj to ground 10 nF
and the 3rd
c) between shdn and cs a resistor of 4.7k
ref to ground 4.7 uF+
refadj to ground 0.1 uF
and from the makers MAXIM it looks like option b)
in all cases i get no data out of the max1270
(or did i just have killed the unit?)
so for that reason i was hoping to get a working schematic from somebody
kind regards
huib
I just wrote a Demo code for it give this a try and let me know if this work
I order some free sample of the MAX1270 and I will them a try my self as well
·This table is the same for the MAX 186 part of what is posted below is from the MAX186 Data Sheet and
·the other part is from the MAX1270 Data Sheet
Table 2. Channel Selection
SEL2···· SEL1····· SEL0········ ·CHANNEL
····X···· X····· X
····· 0··········· 0··········· 0··············· ··········· CH0
····· 0·········· ·0··········· 1······················ ···· CH1
····· 0··········· 1············ 0·························· ·CH2
·····0············ 1············· 1······················ ·· CH3
···· 1·············0············ ·0······················ ·· CH4
··· ·1·············0············ ·1························· ·CH5
···· 1············· 1············ ·0······················ ·· CH6
·····1············· 1·············· 1······················· ··CH7
Bit 7···················· Bit 6···················· ·Bit 5··················· ·Bit 4··················· Bit3············· ·Bit 2·········· ·· Bit 1··········· Bit 0
(MSB)······································································································································································ (LSB)
START·············· SEL2····················· SEL1·············· SEL0··················· ·UNI/BIP··········SGL/DIF···· ··· ·PD1········· PD0
Bit················· Name··················· ·Description
7 (MSB)········· START··············· The first logic "1" bit after CS goes low defines the beginning of the control byte.
6····················· SEL2··················· These three bits select which of the eight channels are used for the conversion.
5····················· SEL1·················· ·See Tables 3 and 4.
4··················· SEL0
3················· UNI/BIP············ 1 = unipolar,······ ·0 = bipolar.······ Selects unipolar or bipolar conversion mode. In unipolar
················································· mode, an analog input signal from 0V to VREF can be converted; in bipolar mode, the
················································· signal can range from -VREF/2 to +VREF/2.
2············· ·SGL/DIF·············1 = single ended,··· ·0 = differential. Selects single-ended or differential conversions. In
·················································· single-ended mode, input signal voltages are referred to AGND. In differential mode,
················································· the voltage difference between two channels is measured. See Tables 3 and 4.
1·············· ··PD1························· Selects clock and power-down modes.
0(LSB········PD0········································ PD1···················· PD0························ Mode
···································································· 0·························· 0····························· Full power-down (IQ = 2μA)· works
···································································· 0························ · 1····························· Fast power-down (IQ = 30μA) works
···································································· 1··························· 0···························· Internal clock mode· works
···································································· 1··························· 1·····························External clock mode
···································································· ^····························· ^····························· ^· This mode dose not work
Example: Simple Software Interface
Make sure the CPU’s serial interface runs in master
mode so the CPU generates the serial clock. Choose a
clock frequency from 100kHz to 2MHz.
1) Set up the control byte for external clock mode, call
it TB1. TB1 should be of the format: 1XXXXX(11··<<<<........ Look at the table·^^ Above ^^·for )
Binary, where the Xs denote the particular channel
and conversion-mode selected.
···································CHANNELs····· unipolar··· single ended
············· START············ ·· ·· SEL0· SEL1··SEL2·········UNI/BIP··· SGL/DIF······ ···· ·PD1·················PD0························
· [noparse][[/noparse]%·· 1········· ·X· X· ·X······ ·1···· · ·1············ ·0······· ·1· ]···Fast power-down
DO
· LOW CS···························································· ··' Enable ADC
· SHIFTOUT DataIn, Clock, MSBFIRST, [noparse][[/noparse]%10001101]···· ·' Select CH0, Single-Ended [noparse][[/noparse]%1XXX1101]
· SHIFTIN DataOut, Clock, MSBPOST, [noparse][[/noparse]result0\12]········ ' Read ADC
· HIGH CS······························································' Disable ADC
· mVolts0 = result0 */ Cnts2Mv·································' Convert To Millivolts
·Please Let me know if this help
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··Thanks for any·
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Sam
Post Edited (sam_sam_sam) : 11/27/2009 2:37:59 AM GMT