Specifications

DATA SHEET QF4A512
Rev D4, Dec 07 57 www.quickfiltertech.com
301h FIR_0_1_COEF_RAM (Coefficients for FIR Filter per Channel, Byte 2)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Channel1 301h C1T1_15 C1T1_14 C1T1_13 C1T1_12 C1T1_11 C1T1_10 C1T1_9 C1T1_8
Channel2 601h C2T1_15 C2T1_14 C2T1_13 C2T1_12 C2T1_11 C2T1_10 C2T1_9 C2T1_8
Channel3 901h C3T1_15 C3T1_14 C3T1_13 C3T1_12 C3T1_11 C3T1_10 C3T1_9 C3T1_8
Channel4 C01h C4T1_15 C4T1_14 C4T1_13 C4T1_12 C4T1_11 C4T1_10 C4T1_9 C4T1_8
*Note, Failure to write addresses 300h, 301, and 302h will result in nothing being written to any of the addresses.
(C1T1_8 - C1T1_15): Represents the middle byte in three bytes storing 20 bits of data.
See Quickfilter software for unique filter design.
Description: This is the LSB of the 20 bit Coefficient Data for the first unique TAP value for the FIR filter. The FIR filter can have
up to 512 taps depending on the filter design. Because the Taps are mirrored, only half of the actual taps are stored in coefficient
RAM. Since most likely it will be an odd number of taps design, the extra "non-mirrored" tap is added to the number of unique
tap coefficients. Example, if a low pass filter design required 137 taps, the number of unique taps would be 137+1 = 138 /2 = 69
unique tap coefficients. Each coefficient is 20 bits, requiring 3 bytes of space for each coefficient. The data is shifted to the
least significant bit.
The next unique Tap value would start at 304h, Unique Tap3 value would start at 307h and so on until all 69 values were entered.
Channel 2: FIR_1_1_COEF_RAM Address 600h
Channel 3: FIR_2_1_COEF_RAM Address 900h
Channel 4: FIR_3_1_COEF_RAM Address C00h
302h FIR_0_1_COEF_RAM (Coefficients for FIR Filter per Channel, MSB, Byte 3)
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Channel1 302h X X X X C1T1_19 C1T1_18 C1T1_17 C1T1_16
Channel2 602h X X X X C2T1_19 C2T1_18 C2T1_17 C2T1_16
Channel3 902h X X X X C3T1_19 C3T1_18 C3P1_17 C3T1_16
Channel4 C02h X X X X C4T1_19 C4T1_18 C4T1_17 C4T1_16
*Note, Failure to write addresses 300h, 301, and 302h will result in nothing being written to any of the addresses.
(C1T1_16 - C1TP1_19): Represents the MSB in three bytes storing 20 bits of data.
Description: This is the LSB of the 20 bit Coefficient Data for the first unique TAP value for the FIR filter. The FIR filter can have
up to 512 taps depending on the filter design. Because the Taps are mirrored, only half of the actual taps are stored in coefficient
RAM. Since most likely it will be an odd number of taps design, the extra "non-mirrored" tap is added to the number of unique tap
coefficients. Example, if a low pass filter design required 137 taps, the number of unique taps would be 137+1 = 138 /2 = 69
unique tap coefficients. Each coefficient is 20 bits, requiring 3 bytes of space for each coefficient. The data is shifted to the
least significant bit.
The next unique Tap value would start at 305h, Unique Tap3 value would start at 308h and so on until all 69 values were entered.
Channel 2: FIR_1_1_COEF_RAM Address 600h
Channel 3: FIR_2_1_COEF_RAM Address 900h
Channel 4: FIR_3_1_COEF_RAM Address C00h