RB9005_amplifier Class Reference
[RB9005 Instrumentation Amplifier]

#include <rb9005_amplifier.h>

Inherits RulbusDevice.

List of all members.

Detailed Description

Purpose

Provide programmable amplifiers and filters to form a data-acquisition system with the high speed 12-bit ADC RB8905.

Description

Module RB9005 is a 4-channel programmable amplifier-filter module.

It contains

When an amplifier is created, it is configured as follows:

Usage

Here is a small example how you may use an amplifier module.

   Rulbus::RB9005_amplfier amplfier( "amplfier" );

   amplfier.setChannel( 1 );
   amplfier.setGain   ( 1, 1000 );
   amplfier.setLowPassFrequency( 1, 10e3 );

Implementation

The programmable amplfiers, filters and multiplexer are controlled via four registers. The following table gives an overview of the module's registers.

   Registers    Offset  Rd/Wr   Description
   -----------------------------------------------------------------------------

   gain12       0       write   register to control gain of differential amplifiers
                                7654     : gain code of channel 1
                                    3210 : gain code of channel 2

   multiplexer  1       write   register to control clock and multiplexer
                                7        : clock sequence (alternate)
                                 6       : channel sequence (autoscan)
                                  543    : channel(s) for sequence
                                     210 : channel on the output

   gain34       2       write   register for gain factor of the single end amplifier.
                                7654     : not used
                                    32   : gain of channel 4
                                      10 : gain of channel 3

   lowpass1     3       write   register for low pass filter channel 1
                                7654     : not used
                                    3210 : low pass frequency

   lowpass2     4       write   register for low pass filter channel 2
                                7654     : not used
                                    3210 : low pass frequency

The following tables describe the meaning of the bits of the fours registers.

   Register   g a i n 1 2

   Code          Gain                   Code          Gain
   ch 1 ch 2                            ch 1 ch 2
   -----------------------------------------------------------------------------
   0000 0000       10                   1000 1000     1000
   0001 0001       20                   1001 1001     2000
   0010 0010       40                   1010 1010     4000
   0011 0011       80                   1011 1011     8000
   0100 0100      100                   1100 1100    10000
   0101 0101      200                   1101 1101    20000
   0110 0110      400                   1110 1110    40000
   0111 0111      800                   1111 1111    80000
   

   Register   l o w p a s s 1,2         Register   g a i n 3 4

   Code         Flp [kHz]               Code           Gain
                                        chan  3  4
   --------------------------------     ----------------------------------------
   xxxx 0000  >= 1000                   xxxx 00 00        1
   xxxx 0001      100                   xxxx 01 01       10
   xxxx 0010       10                   xxxx 10 10      100
   xxxx 0100        1                   xxxx 11 11     1000
   xxxx 1000        0.1
   

   Register   m u l t i p l e x e r

   Code         channel and clock       Code         channel and clock sequence
   -----------------------------------------------------------------------------
   x0xx x000    1                       x100 0xxx    1-> 1-> 1-> 1
   x0xx x001    2                       x100 1xxx    2-> 1-> 2-> 1
   x0xx x010    3                       x101 0xxx    3-> 2-> 1-> 3
   x0xx x011    4                       x101 1xxx    4-> 3-> 2-> 1

   0xxx xxxx    clock out1 = out2       1xxx xxxx    clock out1/out2 alternating

Note: non-sequence selection of channel 4 differs from the original documentation (that specifies pattern x0xx x100).

Method setChannel() sets both the sequence and non-sequence channel bits at the same time and sequencing is enabled or disabled with enableChannelSequence() and enableClockSequence() by setting and clearing the appropriate sequencing bit. Note that the bit-patterns for both channel selections differ!


Public Types

typedef Int Value
 register value type


Public Member Functions

Construction
 RB9005_amplifier (NameCref name, Addr addr=DEF_ADDR, Rack rack=DEF_RACK)
 constructor.

 ~RB9005_amplifier ()
 destructor.

Accessors
int channel () const
 the current channel (1..4).

int gain (int aChannel) const
 the channel's current gain.

Freq lowPassFrequency (int aChannel) const
 the channel's current low pass frequency (channel 1 & 2 only).

bool isChannelSequenceMode () const
 true if a channel sequence is active.

bool isClockSequenceMode () const
 true if a clock sequence is active.

Mutators
void setChannel (int aChannel)
 select specified channel, or channel sequence (1..4).

void setGain (int aChannel, int aGain)
 set gain for specified channel.

void setLowPassFrequency (int aChannel, Freq aFrequency)
 set low pass frequency (channel 1 & 2 only).

void enableChannelSequenceMode (bool enable=true)
 enable or disable channel sequencing.

void enableClockSequenceMode (bool enable=true)
 enable or disable clock sequencing.


Static Public Attributes

Defaults
const Addr DEF_ADDR = 0xB3
 default address

Limits
const Value LIM_MINCHN = 1
 lowest channel number

const Value LIM_MAXCHN = 4
 highest channel number


Protected Member Functions

Construction and Assignment
 RB9005_amplifier ()
 prevent default construction

 RB9005_amplifier (RB9005_amplifierCref rhs)
 prevent copying

RB9005_amplifierRef operator= (RB9005_amplifierCref rhs)
 prevent copying

Tools
void checkChannel (int aChannel) const
 check for valid channel number; may throw RulbusRangeError.

int gain12 (int aChannel) const
 the current gain for channel 1 or 2.

int gain34 (int aChannel) const
 the current gain for channel 3 or 4.

Freq lpf12 (int aChannel) const
 the current low pass frequency for channel 1 or 2.

Freq lpf34 (int aChannel) const
 cannot set/obtain low pass frequency for channels 3 & 4: throws RulbusRangeError.

void setGain12 (int aChannel, int aGain)
 set gain for channel 1 or 2.

void setGain34 (int aChannel, int aGain)
 set gain for channel 3 or 4.

void setLpf12 (int aChannel, Freq aFrequency)
 set low pass frequency for channel 1 or 2; may throw RulbusRangeError.

void setLpf34 (int aChannel, Freq aFrequency)
 cannot set low pass frequency for channels 3 & 4: throws RulbusRangeError.


Private Attributes

Data
Byte theGain12Register
 Channel 1,2 amplifier gain setting.

Byte theGain34Register
 Channel 1,2 amplifier gain setting.

Byte theFreq1Register
 Channel 1 filter setting.

Byte theFreq2Register
 Channel 2 filter setting.

Byte theMuxRegister
 Channel and clock multiplexer setting.


Static Private Attributes

Register offsets
const int OFF_GAIN12 = 0
 Channel 1,2 amplifier gain register offset.

const int OFF_MUX = 1
 Channel and clock multiplexer register offset.

const int OFF_GAIN34 = 2
 Channel 3,4 amplifier gain register offset.

const int OFF_FREQ1 = 3
 Channel 1 filter register offset.

const int OFF_FREQ2 = 4
 Channel 2 filter register offset.

const int ADR_WIDTH = OFF_FREQ2 + 1
 address width

Channel 1,2 gain register
const int MSK_GAIN1 = 0x0F
 1st channel gain selection mask

const int MSK_GAIN2 = 0xF0
 2nd channel gain selection mask

const int SHL_GAIN1 = 0
 1st channel gain shift

const int SHL_GAIN2 = 4
 2nd channel gain shift

Channel 3,4 gain register
const int MSK_GAIN3 = 0x03
 3rd channel gain selection mask

const int MSK_GAIN4 = 0x0C
 4th channel gain selection mask

const int SHL_GAIN3 = 0
 3rd channel gain shift

const int SHL_GAIN4 = 2
 4th channel gain shift

Channel 1,2 filter registers
const int MSK_LPF12 = 0x0F
 1st, 2nd channel low pass filter selection mask

const int SHL_LPF12 = 0
 1st, 2nd channel low pass filter shift

Multiplexer register
const int MSK_CHN1 = 0x07
 1st channel selection mask

const int MSK_CHN2 = 0x38
 2nd channel selection mask

const int MSK_CHNSEQ = 0x40
 channel sequence selection mask

const int MSK_CLKSEQ = 0x80
 clock sequence selection mask

const int SHL_CHN1 = 0
 1st channel shift

const int SHL_CHN2 = 3
 2nd channel shift

Gain & filter tables
const RegInfo GainInfoTable []
 gain masks and shifts for channel 1..4.

const int gain12Table []
 valid gains for channel 1 & 2.

const int gain34Table []
 valid gains for channel 3 & 4.

const Freq freq12Table []
 valid low pass frequencies for channel 1 & 2.

Member Data Documentation

const Freq freq12Table [static, private]
 

Initial value:

   {
      1e6, 100e3, 10e3, 1e3, 0.1e3,
   }

const int gain12Table [static, private]
 

Initial value:

   {
      10, 20, 40, 80,
      100, 200, 400, 800,
      1000, 2000, 4000, 8000,
      10000, 20000, 40000, 80000,
   }

const int gain34Table [static, private]
 

Initial value:

   {
      1, 10, 100, 1000,
   }

const RB9005_amplifier::RegInfo GainInfoTable [static, private]
 

Initial value:

   {
      {       -1,         -1, },        
      { MSK_GAIN1, SHL_GAIN1, },        
      { MSK_GAIN2, SHL_GAIN2, },        
      { MSK_GAIN3, SHL_GAIN3, },        
      { MSK_GAIN4, SHL_GAIN4, },        
   }

The documentation for this class was generated from the following files:
Generated on Tue Oct 12 14:12:05 2004 for Rulbus Device Class Library for Microsoft Windows by doxygen 1.3.4