Difference between revisions of "Modulation Plugin"

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m (→‎Hardware Solution: adding a svn server)
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−
==ToDos==
+
==ToDo==
−
*make sure each components freq. response, to make sure the highest freq.
+
*"Lo" time of DAC can also be set
−
*place DAC into this module board together, then only 4 wires(Vcc, I2C clk, Gnd & I2C data) from host.
+
*modulation cct & PCb
−
*understand all components
+
**Bias resistors for op-amp
−
*call sample
+
**crystal & SMD res. too close, easy to short when soldering
−
*draw circuit and PCB and grounding problem
+
**footprint of some chips are too small, enlarge it for easily soldering
−
*test by real circuit and firmware
+
**some cct modification
 +
***modify the res. value
  
  
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*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 - 10MHz)
 
**Variable amplitude (0V - 2.5V)
 
**Variable amplitude (0V - 2.5V)
 
*interface to MCU which do the control
 
*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 24:
 
**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
  
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===Overall Performance===
 
===Overall Performance===
−
*I2C Baudrate:
+
*I2C Baudrate: 400kHz
−
*Output Voltage Range:
+
*Output Voltage Range: 0 - 3.3V
−
*Output Frequency Range:
+
*Output Frequency Range: 0 - 10MHz
−
*Number of channels:
+
*Number of channels: 4
  
  
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{|border="1" cellspacing="0" cellpadding="5"
 
{|border="1" cellspacing="0" cellpadding="5"
 
|+  
 
|+  
−
!  Part No. !! Description !! Order Chip || Call Sample
+
!  Part No. !! Description
 
|-valign="top"
 
|-valign="top"
−
| [http://focus.ti.com/lit/ds/symlink/dac6574.pdf DAC6574IDGS] || Quad-channel 10-bit I2C DAC || Digikey || No need
+
| [http://focus.ti.com/lit/ds/symlink/dac7574.pdf DAC7574IDGS] || Quad-channel 12-bit I2C DAC
 
|-valign="top"
 
|-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
+
| [http://ww1.microchip.com/downloads/en/DeviceDoc/70165E.pdf dsPIC33FJ256GP506-I/PT] || uP programed as I2C Quad-channel programmable clock[*]
 
|-valign="top"
 
|-valign="top"
−
| [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4474 DS1089L] || 3.3V Center Spread-Spectrum EconOscillator || Digikey || Maxim
+
| [http://focus.ti.com/lit/ds/symlink/sn74ahc4066.pdf SN74AHC4066PWR] || Quad-channel Bilateral Analog Switch
 
|-valign="top"
 
|-valign="top"
−
| [http://www.onsemi.com/pub/Collateral/MC74VHC4051-D.PDF MC74VHC4053DT] || Analog Multiplexers || || Try Contact ON Semiconductor
+
| [http://focus.ti.com/lit/ds/symlink/opa4340.pdf OPA4340EA] || Single-Supply, Quad-channel, Rail-to-Rail Operational Amplifiers
 
|}
 
|}
−
CY2545 is out of stock in digikey, so there is no more information about it.
+
*[*]Alternatives: [http://www.maxim-ic.com/quick_view2.cfm/qv_pk/4474 DS1089L]: 3.3V Center Spread-Spectrum EconOscillator
  
  
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−
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.
  
  
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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>
  
−
===[http://chungyan5.no-ip.org/vc/?root=modulation_plugin SVN SERVER]===
 
−
 
−
==Components Inside Circuit==
 
−
 
−
===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"
 
−
|+ Comparison between Different Clock Generator Chips
 
−
!  Part No. !! Opertating Volt !! Operating Freq !! Min Volt !! Max Volt !! output freq !! Min Temp !! Max Temp !! Pin
 
−
|-valign="top"
 
−
| CY2545 || 2.5V, 3.0V, 3.3V || 400KHz || -0.5V || 4.5V || 3- 166 MHz
 
−
| -40<sup>o</sup>C || 85<sup>o</sup>C || 24-pin
 
−
|-
 
−
| DS1089L || 3.3V || 400KHz || 2.7V || 3.6V || 130kHz - 66.6MHz
 
−
| -40<sup>o</sup>C || 85<sup>o</sup>C || 8-pin
 
−
|}
 
−
CLK 1-8 : frequency output
 
−
  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]              [        ]
 
−
 
−
 
−
===Analog Switch===
 
−
*Part No: MC74VHC4053
 
−
*[http://www.onsemi.com/pub/Collateral/MC74VHC4051-D.PDF datasheet]
 
−
*Switching Frequency: 120MHz
 
−
*No of channels: 4
 
−
*Operating Voltage:
 
−
*Temperature range: -40 - 85<sup>o</sup>C
 
−
 
−
{|border="1" cellspacing="0" cellpadding="5"
 
−
|+ Comparison between Different Analog Switches
 
−
! 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
 
−
|-valign="top"
 
−
| [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
 
−
|-
 
−
| [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
 
−
|-
 
−
| [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
 
−
|-
 
−
| [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
 
−
|-
 
−
| [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
 
−
|-
 
−
|}
 
−
 
−
*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.
 
−
 
−
 
−
===op-amp buffer===
 
−
*OPA340
 
−
 
−
 
−
==Possibly Useful References ==
 
  
−
[http://www.ladyada.net/wiki/openbench/fgen An open source waveform generator]
+
===[http://chungyan5.no-ip.org/vc/?root=modulation_plugin SVN Server]===
 +
*Repository: svn+ssh://chungyan5.no-ip.org/home/open_data/electronic_computer/modulation_plugin/svn_rep
 +
*Contains circuit PCB and software for dsPic Programmable Clock

Revision as of 01:30, 8 December 2008

ToDo

  • "Lo" time of DAC can also be set
  • 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

  • The modulation module is used to deliver a digital output signal with the following characteristics:
    • Square wave
    • Variable frequency (0 - 10MHz)
    • Variable amplitude (0V - 2.5V)
  • interface to MCU which do the control


Software Solution

  • 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

Overall Performance

  • I2C Baudrate: 400kHz
  • Output Voltage Range: 0 - 3.3V
  • Output Frequency Range: 0 - 10MHz
  • Number of channels: 4


Selected Chips

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


Circuit

                    +-----+            +--------+         +--------+
      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

  • 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


SVN Server

Retrieved from "http://www.opencircuits.com/index.php?title=Modulation_Plugin&oldid=16927"