wiki:crkit/Hardware/RFBoards/aSDR1

SDR with Frequency Extension Board (eSDR)

Block-diagram of SDR with frequency extension is shown in Figure 1.

Extended Frequency SDR Board Block Diagram

FreeBo Registers

FreeBo registers are shown in the following table:

+-----------------------+------------+----------+------+------+---------------------------------------------+
|Name                   | Address    | # of Reg | Bits | Description                                        |
+=======================+============+==========+======+====================================================+
| ADF4350 VCO           | 200 to 223 |    24    |  8   | The original 6 x 32-bit LO registers are mapped    |
|                       |            |          |      | to 8 bit buss with the following mapping:          |
|                       |            |          |      | R0: 200 -203, R1: 204 -207, R2: 208-211,           |
|                       |            |          |      | R3: 212 -215, R4: 216 -219, R5: 220-223            | 
+-----------------------+------------+----------+------+----------------------------------------------------+
| MAX7301 RF Switch     | 224 to 247 |    24    |  8   | 12 x 16-bit registers are mapped to 24 8-bit regs  |
|                       |            |          |      | R0: 224-225,R1: 226-227,R2: 228-229,               |
|                       |            |          |      | R3: 230-231, R4: 232-233,R5: 234-235,              | 
|                       |            |          |      | R6: 236-237, R7: 238-239,R8: 240-241,              | 
|                       |            |          |      | R9: 242-243, R10: 244-245, R11: 246-247            | 
+-----------------------+------------+----------+------|----------------------------------------------------+
|Hittit HMC629          |     1      |     1    |  8   |The upper 4 bits program the RX attenuator while the|
|RF Attenuator          |            |          |      |the lower 4 bits control the TX attenuator.         |
+-----------------------+------------+----------+------|----------------------------------------------------+

For example, to generate Fout = 3314.705 MHz (plus other LO default values), configure six registers as shown below:

  • R0: 00000000101001011001110101101000
  • R1: 00001000000000001011111010000001
  • R2: 00000001000000000101111011000010
  • R3: 00000000000000000000010010110011
  • R4: 00000000100001010000000111111100
  • R5: 00000000010110000000000000000101

For example, to initialize the MAX7301 chip configure the first eight registers as in the following.

  • R0: 0000010000000001
  • R1: 0000100101010101
  • R2: 0000101001010101
  • R3: 0000001101010101
  • R4: 0000110001010101
  • R5: 0000110101010101
  • R6: 0000011001010101
  • R7: 0000111101010101

To generate default setting (straight through setting) use the following configuration.

  • R8: 0100010001000000 /RX switch straight
  • R9: 0100110001000000 /TX switch straight
  • R10: 0101010000000000 /don't care
  • R11: 0101110000000000 /don't care

To generate crossed-switch setting (inputs crossed over) use the following configuration.

  • R8: 0100010000100000 /RX switch cross
  • R9: 0100110000100000 /TX switch cross
  • R10: 0101010000000000 /don't care
  • R11: 0101110000000000 /don't care

For example, “11111111” corresponds to lowest attenuation level, i.e., the maximum FreeBo? gain while setting it to “10100000”, corresponds to 15 dB receiver attenuation and 45 dB of transmitter attenuation.

Last modified 8 years ago Last modified on 06/16/10 21:33:14

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