Difference between revisions of "Modulation Plugin"

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==ToDos==
+
This project aims to develop an Modulation Plugin Module, to be used in conjunction with a 8/16 bits embedded system such as the dsPic33F development board.
*make sure each components freq. response, to make sure the highest freq.  
+
 
*place DAC into this module board together, then only 4 wires(Vcc, I2C clk, Gnd & I2C data) from host.  
+
==ToDo==
*understand all components
+
*Voltage during "Lo" time of DAC can also be set (i.e. not necessary zero)
*call sample
+
*modulation cct & PCb
*draw circuit and PCB and grounding problem
+
**Bias resistors for op-amp
*test by real circuit and firmware
+
**crystal & SMD res. too close, easy to short when soldering
 +
**footprint of some chips are too small, enlarge it for easily soldering
 +
**some cct modification
 +
***modify the res. value
  
  
Line 11: Line 14:
 
*The modulation module is used to deliver a digital output signal with the following characteristics:
 
*The modulation module is used to deliver a digital output signal with the following characteristics:
 
**Square wave
 
**Square wave
**Variable frequency (>1kHz)
+
**Variable frequency (0 - >10kHz)
 
**Variable amplitude (0V - 2.5V)
 
**Variable amplitude (0V - 2.5V)
*interface to MCU which do the control
+
**Accuracy frequency response (error < 2%)
 
+
*Interface to MCU which do the control
 
 
*Q: Is square wave where the "Lo" time is always at "GND" OK?
 
*Q: If not, is a switch between "Lo is GND" vs. "Lo is negative Hi" OK? Or does "Lo" need to be independently controlled with another ADC?
 
*Q: Will people be connecting a speaker directly to the output, requiring a relatively high-power output [[op amp]] such as the LM386N-3 ?
 
  
  
 
==Software Solution==
 
==Software Solution==
*Timer Interrupt controlling I2C 10-bit DAC can only achieve frequency response of about 1kHz
+
*Timer Interrupt controlling I2C DAC can only achieve frequency response of about 500Hz
 
**5byte/cmd
 
**5byte/cmd
 
**8bit/byte
 
**8bit/byte
Line 28: Line 27:
 
**This yields 10kHz (0.1ms)
 
**This yields 10kHz (0.1ms)
 
**As OS context switch is 10ms, set timer to 1ms (1kHz), so that 0.9ms can be used to process other tasks
 
**As OS context switch is 10ms, set timer to 1ms (1kHz), so that 0.9ms can be used to process other tasks
 +
**timer frequency of 1kHz yields a modulation frequency of 500Hz
 
*Due to higher freq. response requirement, so using hardware to implement the clock
 
*Due to higher freq. response requirement, so using hardware to implement the clock
  
Line 33: Line 33:
 
==Hardware Solution==
 
==Hardware Solution==
  
===Overall Performance===
 
*I2C Baudrate:
 
*Output Voltage Range:
 
*Output Frequency Range:
 
*Number of channels:
 
 
 
===Selected Chips===
 
{|border="1" cellspacing="0" cellpadding="5"
 
|+
 
!  Part No. !! Description !! Order Chip || Call Sample
 
|-valign="top"
 
| [http://focus.ti.com/lit/ds/symlink/dac6574.pdf DAC6574IDGS] || Quad-channel 10-bit I2C DAC || Digit Key || No need
 
|-valign="top"
 
| [http://download.cypress.com.edgesuite.net/design_resources/datasheets/contents/cy2545_8.pdf CY2545???] || Quad PLL I2C Programmable Clock Generator || HQEW || Try Contact Cypress
 
|-valign="top"
 
| [http://www.onsemi.com/pub/Collateral/MC74VHC4051-D.PDF MC74VHC4053DT] || Analog Multiplexers || || Try Contact ON Semiconductor
 
|}
 
CY2545 is out of stock in digikey, so there is no more information about it.
 
  
 
===Circuit===
 
===Circuit===
Line 67: Line 48:
 
    
 
    
  
This architecture allows the square wave to run at a very high frequency, even with a slow I2C and a slow DAC.
+
*This architecture allows the square wave to run at a very high frequency, even with a slow I2C and a slow DAC.
  
  
Line 98: Line 79:
 
w 272 128 336 128 0
 
w 272 128 336 128 0
 
w 176 256 176 144 0
 
w 176 256 176 144 0
r 272 224 272 288 0 1000.0
+
r 272 224 272 288 0 10000.0
 
w 272 128 272 224 0
 
w 272 128 272 224 0
 
w 272 288 272 352 0
 
w 272 288 272 352 0
 
159 144 128 208 128 0
 
159 144 128 208 128 0
r 208 128 256 128 0 1000.0
+
r 208 128 256 128 0 10000.0
 
w 256 128 272 128 0
 
w 256 128 272 128 0
 
w 144 256 176 256 0
 
w 144 256 176 256 0
r 336 224 336 288 0 1000.0
+
r 336 224 336 288 0 10000.0
 
g 336 352 336 368 0
 
g 336 352 336 368 0
 
w 336 288 336 352 0
 
w 336 288 336 352 0
 
w 336 192 336 224 0
 
w 336 192 336 224 0
r 352 192 432 192 0 1000.0
+
r 352 192 432 192 0 10000.0
o 4 64 0 34 2.5 7.8125E-4 0 -1
+
o 4 64 0 34 2.5 9.765625E-5 0 -1
 
o 0 64 0 35 5.0 9.765625E-5 1 -1
 
o 0 64 0 35 5.0 9.765625E-5 1 -1
o 11 64 0 34 2.5 0.0015625 2 -1
+
o 11 64 0 34 2.5 3.90625E-4 2 -1
 
</nowiki></pre>
 
</nowiki></pre>
  
  
==Components Inside Circuit==
+
===Selected Chips===
 
 
===DAC chip===
 
*Part No: DAC6574IDGS
 
*[http://focus.ti.com/lit/ds/symlink/dac6574.pdf datasheet]
 
*Resolution: 10-bit
 
*I2C clock Frequency: upto 3.4Mbps
 
*No of channels: 4
 
*Operating Voltage: 2.7 - 5.5V
 
*Temperature range: -40 - 105<sup>o</sup>C
 
 
 
 
 
===Clock Generator chip===
 
*CY2545???
 
*[http://download.cypress.com.edgesuite.net/design_resources/datasheets/contents/cy2545_8.pdf datasheet]
 
*buy at [http://new.hqew.com/Web/Public/Buyer/ICStockSearch.aspx?keyword=cy2545 here]
 
*I2C clock Frequency: upto 400kbps
 
*No of channels: 4
 
*Operating Voltage: 2.5V, 3.0V, 3.3V
 
*Temperature range: -40 - 85<sup>o</sup>C
 
 
 
 
{|border="1" cellspacing="0" cellpadding="5"
 
{|border="1" cellspacing="0" cellpadding="5"
|+ Comparison between Different Clock Generator Chips
+
|+  
!  Part No. !! Opertating Volt !! Operating Freq !! Min Volt !! Max Volt !! output freq !! Min Temp !! Max Temp !! Pin
+
!  Part No. !! Description
 
|-valign="top"
 
|-valign="top"
| CY2545 || 2.5V, 3.0V, 3.3V || 400KHz || -0.5V || 4.5V || 3- 166 MHz
+
| [http://ww1.microchip.com/downloads/en/DeviceDoc/70165E.pdf dsPIC33FJ256GP506-I/PT] || uP programed as I2C Quad-channel programmable clock[*]
| -40<sup>o</sup>C || 85<sup>o</sup>C || 24-pin
+
|-valign="top"
 +
| [http://focus.ti.com/lit/ds/symlink/dac7574.pdf DAC7574IDGS] || Quad-channel 12-bit I2C DAC
 +
|-valign="top"
 +
| [http://focus.ti.com/lit/ds/symlink/sn74ahc4066.pdf SN74AHC4066PWR] || Quad-channel Bilateral Analog Switch
 +
|-valign="top"
 +
| [http://focus.ti.com/lit/ds/symlink/opa4340.pdf OPA4340EA] || Single-Supply, Quad-channel, Rail-to-Rail Operational Amplifiers
 
|}
 
|}
CLK 1-8 : frequency output
+
*[*]Alternatives: [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4474 DS1089L]: 3.3V Center Spread-Spectrum EconOscillator
  CLK 3 : frequency selection (FS)
 
          (Function 2) cy2545 has 4 PLLs, each PLLs can be set 2 frequency, CLK 3 use to select the frequency
 
  CLK 6 : spread spectrum ON/OFF control input
 
          (Function 2) for synthesizing and modulating the frequency
 
Vdd_CLK_BX (X=1,2,3) control the output frquency of Blanck X (X=1,2,3)
 
 
                +------------------+       
 
                |        |        |------CLK 1
 
                |        | Bank 1 |
 
                |        |        |------CLK 2
 
                |------------------|   
 
                |        |        |------CLK 3
 
                |        | Bank 2 |------CLK 4
 
                |        |        |------CLK 5
 
                |------------------|
 
                |        |        |------CLK 6
 
                |        | Bank 3 |------CLK 7
 
                |        |        |------CLK 8
 
                +------------------+
 
CLKIN/RST ---1. 2.5V/3.0V/3.3V external reference clock frequency
 
              2. Reset function POR :back to default condition /
 
                        Clean Start : keep the programmed value
 
Xout        Crystal frequency output
 
Xin/EXCLKIN Crystal frequency input/ 1.8V external clock input
 
  
*Coding
 
  [Start Bit]->[7-bits devices]-->[R/W bit]-->[  Slave  ]-->[  8-bits    ]--> .. 
 
  [ address ]  [  address    ]  [      ]  [ CLK ACK ]  [memory address] 
 
 
 
  ..[ACK]-->[8-bits]-->[  8-bits    ]-->....[  8-bits    ]......until... [stop bit]
 
    [  ]  [ data ]  [data in MA+1]      [data in MA+n]              [        ]
 
  
 +
===Overall Performance===
  
===Analog Switch===
+
====dsPic Programmable Clock====
*Part No: MC74VHC4053
+
*I2C Baudrate: 400kHz
*[http://www.onsemi.com/pub/Collateral/MC74VHC4051-D.PDF datasheet]
+
*Output Voltage Range: 0 - 3.3V
*Switching Frequency: 120MHz
+
*Output Frequency Range: 0 - 200kHz
*No of channels: 4
+
**Cannot reach higher frequency due to minimum time to execute code in interrupt routine is about 500ns
*Operating Voltage:  
+
*Number of channels: 4
*Temperature range: -40 - 85<sup>o</sup>C
+
*Accuracy of frequency: <2%
 
+
**Conditions: external crystal, no OS context switch, single channel operation
{|border="1" cellspacing="0" cellpadding="5"
+
**Measurements (by scope)
|+ Comparison between Different Analog Switches
+
***+/-2.100kHz@200kHz => 1.05%
! Part No. !! Operating Volt(V) !! Freq Resp(Hz) at 3V !! On-state Resist(Ω) at 3V !! Min Volt(V) !! Max Volt(V) !! Min Temp !! Max Temp !! Indenpent Circuit !! Voltage Supply Source !! Pin
+
***+/-0.520kHz@100kHz => 0.52%
|-valign="top"
+
***+/-0.140kHz@50kHz => 0.28%
| [http://focus.ti.com/lit/ds/symlink/sn74ahc4066.pdf SN74AHC4066] || Vcc : 2V~5.5V || 35MHz || 29Ω || Vcc : -0.5V || Vcc :  7V||-40<sup>o</sup>C || 85<sup>o</sup>C || 4 || single || 14
+
***+/-0.006kHz@10kHz => 0.06%
|-
+
***+/-0.002kHz@5kHz => 0.04%
| [http://www.nxp.com/acrobat_download/datasheets/74HC_HCT4051_3.pdf 74HC4051D] || Vcc : 2V~10V Vee : -10V~2V || Nil || 80Ω || Vcc :-0.5V Vee : -11V  || Vcc :  11V Vee :  2V ||-40<sup>o</sup>C || 85<sup>o</sup>C || 4 || Dual || 16
+
***+/-0.200Hz@1000Hz => 0.02%
|-
+
***+/-0.000Hz@500Hz => 0.00%
| [http://www.onsemi.com/pub/Collateral/MC74VHC4051-D.PDF MC74VHC''4051''] || Vcc : 2V~6V Vee : -6V~0V || 80MHz || 80Ω || Vcc :-0.5V Vee :-7V  || Vcc :  7V Vee : 5V ||-40<sup>o</sup>C || 85<sup>o</sup>C || 4 || Dual || 16
+
***+/-0.000Hz@100Hz => 0.00%
|-
+
***+/-0.0001Hz@50Hz => 0.02%
| [http://www.onsemi.com/pub/Collateral/MC74VHC4051-D.PDF MC74VHC''4052''] || Vcc : 2V~6V Vee : -6V~0V || 90MHz || 90Ω || Vcc :-0.5V Vee :-7V  || Vcc : 7V Vee : 5V ||-40<sup>o</sup>C || 85<sup>o</sup>C || 4 || Dual || 16
+
***+/-0.000Hz@10Hz => 0.00%
|-
+
***+/-0.000Hz@5Hz => 0.00%
| [http://www.onsemi.com/pub/Collateral/MC74VHC4051-D.PDF MC74VHC''4053''] || Vcc : 2V~6V Vee : -6V~0V || 120MHz || 90Ω || Vcc :-0.5V Vee :-7V  || Vcc : 7V Vee : 5V ||-40<sup>o</sup>C || 85<sup>o</sup>C || 4 || Dual || 16
+
*Accuracy of frequency: <2%
|-
+
**Conditions: external crystal, no OS context switch, 4 channel operation, Ch2 = 1kHz, Ch3 = 50kHz, Ch4 = 200kHz
|}
+
**Measurements of ch1 (by scope)
 +
***+/-2.000kHz@200kHz => 1.00%
 +
***+/-0.520kHz@100kHz => 0.52%
 +
***+/-0.130kHz@50kHz => 0.26%
 +
***+/-0.130kHz@10kHz => 0.06%
 +
***+/-0.002kHz@5kHz => 0.04%
 +
***+/-0.200Hz@1000Hz => 0.02%
 +
***+/-0.100Hz@500Hz => 0.02%
 +
***+/-0.000Hz@100Hz => 0.00%
 +
***+/-0.010Hz@50Hz => 0.01%
 +
***+/-0.000Hz@10Hz => 0.00%
 +
***+/-0.001Hz@5Hz => 0.02%
  
*more information about the series 7400 in wiki: http://en.wikipedia.org/wiki/7400_series
 
*there is model G which is super high speeds at more than 1 GHz in 7400 family, however this model is very expensive.
 
  
 +
===[http://chungyan5.no-ip.org/vc/?root=modulation_plugin SVN Server]===
 +
*Contains circuit PCB and software
 +
====Version 1.00.01====
 +
*dsPic programmable clock + dac + analog switch + op-amp
 +
====Version 2.02.00====
 +
*dsPic programmable clock only.
 +
*dac + analog switch + op-amp introduce bouncing noise spikes when switching.
 +
*New board provides trigger signal to external circuitry only.
  
===op-amp buffer===
+
===Testing Procedure===
*OPA340
 
  
 +
====Version 1.00.01====
 +
*For each channel (ch 1 - 4) at pin H2.1, H2.3, H2.5, H2.7
 +
**Use a CRO to watch the signal
 +
***Enable the channel
 +
***Adjust the voltage from 0 - 2.5V (measure accuracy).
 +
***Adjust the frequency from DC - 200kHz (measure accuracy). If frequency is not accurate, check crystal circuitry.
  
==Possibly Useful References ==
 
  
[http://www.ladyada.net/wiki/openbench/fgen An open source waveform generator]
+
[[category:projects]]

Latest revision as of 23:35, 25 April 2012

This project aims to develop an Modulation Plugin Module, to be used in conjunction with a 8/16 bits embedded system such as the dsPic33F development board.

ToDo[edit]

  • Voltage during "Lo" time of DAC can also be set (i.e. not necessary zero)
  • modulation cct & PCb
    • Bias resistors for op-amp
    • crystal & SMD res. too close, easy to short when soldering
    • footprint of some chips are too small, enlarge it for easily soldering
    • some cct modification
      • modify the res. value


Objectives[edit]

  • The modulation module is used to deliver a digital output signal with the following characteristics:
    • Square wave
    • Variable frequency (0 - >10kHz)
    • Variable amplitude (0V - 2.5V)
    • Accuracy frequency response (error < 2%)
  • Interface to MCU which do the control


Software Solution[edit]

  • Timer Interrupt controlling I2C DAC can only achieve frequency response of about 500Hz
    • 5byte/cmd
    • 8bit/byte
    • baudrate = 400kHz
    • This yields 10kHz (0.1ms)
    • As OS context switch is 10ms, set timer to 1ms (1kHz), so that 0.9ms can be used to process other tasks
    • timer frequency of 1kHz yields a modulation frequency of 500Hz
  • Due to higher freq. response requirement, so using hardware to implement the clock


Hardware Solution[edit]

Circuit[edit]

                    +-----+            +--------+         +--------+
      I2C Bus       |     |            | Analog |         | Op-Amp |
  ------------+-----| DAC |------------| Switch |---------|        |---------Output
              |     |     |            +--------+         +--------+
              |     +-----+                |
              |                            |
              |     +--------------+       |
              |     | Programmable |       |
              +-----| Clock        |-------+
                    +--------------+
  
  • This architecture allows the square wave to run at a very high frequency, even with a slow I2C and a slow DAC.


Circuit Simulation by Paul Falstad's Web[edit]

  • Import the following
$ 1 5.0E-6 16.817414165184545 64 5.0 50
w 128 256 144 256 0
w 16 256 64 256 0
g 16 352 16 368 0
v 64 64 112 64 0 0 40.0 2.5 0.0 0.0 0.5
w 112 128 144 128 0
w 64 128 16 128 0
w 16 128 16 256 0
v 64 256 128 256 0 2 1000.0 1.65 1.65 0.0 0.5
a 336 144 464 144 1 3.3 0.0
w 336 160 336 192 0
w 464 192 464 144 0
w 464 144 512 144 0
r 592 144 592 256 0 1000.0
g 592 352 592 368 0
w 512 144 592 144 0
w 336 192 352 192 0
w 432 192 464 192 0
v 64 128 112 128 0 1 1.0 1.25 1.25 0.0 0.5
w 16 256 16 288 0
w 16 288 16 352 0
w 592 256 592 352 0
g 272 352 272 368 0
w 272 128 336 128 0
w 176 256 176 144 0
r 272 224 272 288 0 10000.0
w 272 128 272 224 0
w 272 288 272 352 0
159 144 128 208 128 0
r 208 128 256 128 0 10000.0
w 256 128 272 128 0
w 144 256 176 256 0
r 336 224 336 288 0 10000.0
g 336 352 336 368 0
w 336 288 336 352 0
w 336 192 336 224 0
r 352 192 432 192 0 10000.0
o 4 64 0 34 2.5 9.765625E-5 0 -1
o 0 64 0 35 5.0 9.765625E-5 1 -1
o 11 64 0 34 2.5 3.90625E-4 2 -1


Selected Chips[edit]

Part No. Description
dsPIC33FJ256GP506-I/PT uP programed as I2C Quad-channel programmable clock[*]
DAC7574IDGS Quad-channel 12-bit I2C DAC
SN74AHC4066PWR Quad-channel Bilateral Analog Switch
OPA4340EA Single-Supply, Quad-channel, Rail-to-Rail Operational Amplifiers
  • [*]Alternatives: DS1089L: 3.3V Center Spread-Spectrum EconOscillator


Overall Performance[edit]

dsPic Programmable Clock[edit]

  • I2C Baudrate: 400kHz
  • Output Voltage Range: 0 - 3.3V
  • Output Frequency Range: 0 - 200kHz
    • Cannot reach higher frequency due to minimum time to execute code in interrupt routine is about 500ns
  • Number of channels: 4
  • Accuracy of frequency: <2%
    • Conditions: external crystal, no OS context switch, single channel operation
    • Measurements (by scope)
      • +/-2.100kHz@200kHz => 1.05%
      • +/-0.520kHz@100kHz => 0.52%
      • +/-0.140kHz@50kHz => 0.28%
      • +/-0.006kHz@10kHz => 0.06%
      • +/-0.002kHz@5kHz => 0.04%
      • +/-0.200Hz@1000Hz => 0.02%
      • +/-0.000Hz@500Hz => 0.00%
      • +/-0.000Hz@100Hz => 0.00%
      • +/-0.0001Hz@50Hz => 0.02%
      • +/-0.000Hz@10Hz => 0.00%
      • +/-0.000Hz@5Hz => 0.00%
  • Accuracy of frequency: <2%
    • Conditions: external crystal, no OS context switch, 4 channel operation, Ch2 = 1kHz, Ch3 = 50kHz, Ch4 = 200kHz
    • Measurements of ch1 (by scope)
      • +/-2.000kHz@200kHz => 1.00%
      • +/-0.520kHz@100kHz => 0.52%
      • +/-0.130kHz@50kHz => 0.26%
      • +/-0.130kHz@10kHz => 0.06%
      • +/-0.002kHz@5kHz => 0.04%
      • +/-0.200Hz@1000Hz => 0.02%
      • +/-0.100Hz@500Hz => 0.02%
      • +/-0.000Hz@100Hz => 0.00%
      • +/-0.010Hz@50Hz => 0.01%
      • +/-0.000Hz@10Hz => 0.00%
      • +/-0.001Hz@5Hz => 0.02%


SVN Server[edit]

  • Contains circuit PCB and software

Version 1.00.01[edit]

  • dsPic programmable clock + dac + analog switch + op-amp

Version 2.02.00[edit]

  • dsPic programmable clock only.
  • dac + analog switch + op-amp introduce bouncing noise spikes when switching.
  • New board provides trigger signal to external circuitry only.

Testing Procedure[edit]

Version 1.00.01[edit]

  • For each channel (ch 1 - 4) at pin H2.1, H2.3, H2.5, H2.7
    • Use a CRO to watch the signal
      • Enable the channel
      • Adjust the voltage from 0 - 2.5V (measure accuracy).
      • Adjust the frequency from DC - 200kHz (measure accuracy). If frequency is not accurate, check crystal circuitry.