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ADC12DJ3200EVM: Question on JMODE Documentation

Zachary Dryer
Prodigy 135 points
Part Number: ADC12DJ3200EVM
Other Parts Discussed in Thread: ADC12DJ3200

I am looking at some code that resembles JMODE0 Table 20. (page 66) of the ADC12DJ3200 documentation but I don't know where they get the bit ranges.

This is what is looks like:

s0    31:20    s8    19:8    s16    7:0            31:28        s24    27:16    s32    15:4    3:0
s2    63:52    s10    51:40    s18    39:32        63:60        s26    59:48    s34    47:36    35:32
s4    95:84    s12    83:72    s20    71:64        95:92        s28    91:80    s36    79:68    67:64
s6    127:116    s14    115:104    s22    103:96        127:124        s30    123:112    s38    111:100    99:96
s1    159:148    s9    147:136    s17    135:128        159:156        s25    155:144    s33    143:132    131:128
s3    191:180    s11    179:168    s19    167:160        191:188        s27    187:176    s35    175:164    163:160
s5    223:212    s13    211:200    s21    199:192        223:220        s29    219:208    s37    207:196    195:192
s7    255:244    s15    243:232    s23    231:224        255:252        s31    251:240    s39    239:228    227:224

Where do I find out the ranges? For example for s0 they have 31:20 where do they get this? Is this in the documentation?

Also is there a place I can get this so I can reverse engineer this pattern for JMODE 11?

Thanks,

Zach

  • 0
    TI__Mastermind 44680 points
    Hi Zach
    I'm working on your question. I'll have a more detailed response later today.
    Best regards,
    Jim B
  • 0 in reply to Jim Brinkhurst1
    TI__Mastermind 44680 points
    Hi Zach
    That portion of code appears to be parsing the sample data out of 1 data frame into the individual samples from 0 to 39. The JESD204 IP will output a 32-bit parallel word for every 4 octets of data that are deserialized. So there are 2 parallel words for every 8-octet frame period. That is why the parsing is broken up into 2 groups of bits from 0 to 255. (left and right sides of the pattern)
    For JMODE11 one data frame is only 2 octets long. So there will be 2 data frames in every 32 bit parallel word output from the JESD204 IP. In 2 frames the samples in JMODE11 will be as follows:

    AI0 31:16 AI2 15:0
    AI1 63:48 AI3 47:32
    AQ0 95:80 AQ2 79:64
    AQ1 127:112 AQ3 111:96
    BI0 159:144 BI2 143:128
    BI1 191:176 BI3 175:160
    BQ0 223:208 BQ2 207:192
    BQ1 255:240 BQ3 239:224

    This pattern will repeat to the with higher numbered samples if you want to process larger blocks of data (more frames) at one time.

    I hope this is helpful.
    Best regards,
    Jim B