37.7.6 CVD Results Descriptor FIFO Read Register
Name: | CVDRESD |
Offset: | 0x018 |
Reset: | 0x00000000 |
Property: | - |
Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
TXINDEX[4:0] | SDNUM[1:0] | ||||||||
Access | R | R | R | R | R | R | R | ||
Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
RXINDEX[4:0] | DELTA[17:16] | ||||||||
Access | R | R | R | R | R | R | R | ||
Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
DELTA[15:8] | |||||||||
Access | R | R | R | R | R | R | R | R | |
Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
DELTA[7:0] | |||||||||
Access | R | R | R | R | R | R | R | R | |
Reset | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
Bits 31:27 – TXINDEX[4:0] Transmit Index of the result
Bits 25:24 – SDNUM[1:0] Scan Descriptor Number
Bits 23:19 – RXINDEX[4:0] Receive Index of the result
Bits 17:0 – DELTA[17:0] Delta of the accumulated results of the negative-side and positive-side measurements
The DELTA presented is the 18 MSBs (including sign bit) of a signed subtraction of the two accumulators. The data will be in 2’s complement form if the delta is negative.
Width Needed: ADCBITS + 7 + 1 (sign)
Width available: 18
delta_pre[ADCBITS+7:0] = signed’( {1’b0, POS[ADCBITS+7-1:0]} - {1’b0, NEG[ADCBITS+7-1:0]} )
DELTA[17:0] = delta_pre[ADC_BITS+7:ADC_BITS+7-17]
Note: Reading this register increments
the FIFO read pointer, destroying the data in the previous two registers for NEG
and POS absolute values. If the NEG and POS values are desired, those registers
must be read before this register. If the absolute values are not required,
bandwidth can be saved by reading only this descriptor
register.