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Block diagram of EtherPod:

Block diagram.png

Circuit board dimensions compatible with Tyco Snaptrack (2TK2), which can then be fastened to a DIN rail.

Connector Pin Assignments

P1 to P4 - Axis Connectors

Where the "x", below,is 1 to 4 corresponding to the axis.

Pin Function
2 DIOx0
3 DIOx1
4 DIOx2
5 DIOx3
6 ChxA+
7 ChxA-
8 ChxB+
9 ChxB-
10 Indx_x+
11 Indx_x-
12 +5 Volts
13 A_out_x
14 A_in_x_0
15 A_in_x_1

On the circuit board the analog ground (AGND) goes first to the analog chips and is connected with the digital ground (DGND) at a single point. The digital I/O (DIO_xx) are three volt signals--don't put 5 volt signals there. The +5 volt output is intended to power the quadrature encoder; the encoder inputs will tolerate 5 volts.

P5 - Power

Pin Function
2 NC
3 +5 Volts
4 -12 Volts
5 +12 Volts

Switching power supplies typically have a minimum load current, and the Etherpod draws less than most require. Here are some options:

  • Cosel Power Supplies, Triple Output RMC Series, RMC15A-1, no minimum load needed. Screw terminals make this easy to use.
  • TDK-Lambda MTW15-51212, no minimum current needed.
  • Cosel Power Supplies, Triple Output, Model #: PMC15E-1. We meet minimum current requirement for +5, no minimum for +/- 12.

P6 Aux Digital I/O

Pin Function

P6 brings out unused pins from the Netburner 5270. Anticipated use is for timing tests, where software modules set these bits (configured as digital I/O) and the results are observed on an oscilloscope. The QSPI bus is also on this connector for testing purposes.


Mini-USB to download software to CPU Module.

P9 Battery Backup

Optional battery to back up counts. Only 24 bits are held, software extensions to 32 bits not backed up.

Pin Function
2 +5 to +10 Volts

Quadrature Counter

Our quadrature encoder counter is implemented with an LS7566 from LSI Computer Systems Inc. The datasheet is LS7566R.pdf, where you can find further details.

Input is through a MAX 3096 differential receiver. The data sheet, MAX3095-MAX3096.pdf, can be found at

Input circuit:

Cntr input.png

When using a single ended encoder output hook the signal to the "+" input. Leave the "-" input unconnected. Do not ground it. Let voltage divider will pull the input to an intermediate voltage, so the "+" input will cleanly cross it.

The +5 Volt output on the axis connectors is intended to power the encoders. An SMD005 (microSMD005F) resettable fuse is in series with each +5 line, which triggers at about 150 ma. Hold current is about 50 ma.

Digital I/0

I/O protection circuit:

Dio protection.png

Relevant data sheets: SMDDS.pdf, NUP4302MR6.PDF.

We placed the DIO on dual purpose pins in case the other function is desired for some special purpose.

DIO Assignments to NetBurner module

DIO pin Module Pin NB Pin Module Port Alternate Function
DIO_0_0 (B21) J2[21] PUARTL[4] UART 1 Rx
DIO_0_1 (B22) J2[22] PUARTL[5] UART 1 TX
DIO_0_2 (B32) J2[32] PUARTL[6] UART 1 RTS
DIO_0_3 (B43) J2[43] EPDR[1] IRQ 1
DIO_1_0 (B41) J2[41] PUARTH[0] UART 2 RX
DIO_1_1 (B44) J2[44] PUARTH[1] UART 2 TX
DIO_1_2 (B37) J2[37] PTIMER[3] DMA Timer 1 In/Out
DIO_1_3 (B45) J2[45] EPDR[3] IRQ 3
DIO_2_0 (B36) J2[36] PTIMER[0] DMA Timer 0 Out
DIO_2_1 (B31) J2[31] PTIMER[1] DMA Timer 0 In
DIO_2_2 (B35) J2[35] PTIMER[5] DMA Timer 2 In/Out
DIO_2_3 (B47) J2[47] EPDR[5] IRQ 5
DIO_3_0 (B39) J2[39] FECI2C[0] I2C Data
DIO_3_1 (B42) J2[42] FECI2C[1] I2C Clock
DIO_3_2 (B26) J2[26] PTIMER[6] DMA Timer 3 Out
DIO_3_3 (B48) J2[48] EPDR[7] IRQ 7

Analog Out

The analog output section is implemented by an Analog Devices AD5754R integrated circuit. Datasheet: AD5724R_5734R_5754R.pdf.

Protection circuit:

Analog out.png

Other relevant datasheets: lm324.pdf, SMDDS.pdf, NUP4302MR6.PDF.

Analog In

The analog input section is implemented by an Analog Devices AD7607 integrated circuit. Datasheet: AD7607.pdf.

Protection circuit and low pass filter:

Analog in.png

-3dB frequency = 1 / (2 * pi * RC) = 1 / ( 2 * 3.14 * 0.01 * 10E-6 * 100) ~= 16 KHz.

Other relevant datasheets: SMDDS.pdf, NUP4302MR6.PDF.

Netburner Notes

New Netburner modules should be initialized with IPsetup to IP address, netmask