Texas Instruments MSP50C6xx User Manual
Page 153
Special Filter Instructions
4-67
Assembly Language Instructions
Figure 4–6. Setup and Execution of MSP50P614/MSP50C614 Filter Instructions,
N+1 Taps
Accumulators
0–15
th
bits of y
Ĕ
16–31
st
bits of y
Ĕ
32–47
th
bits of y
Ĕ
ACr
ACr+1
ACr+2
y[k] =
Σ
m =0..N
h[m]x[k–m]
+
Multiplier
PH
MR
ОООООО
ОООООО
ОООООО
ОООООО
ОООООО
ОООООО
ОООООО
ОООООО
ОООООО
Past N samples,
x[k]
ОООООО
ОООООО
ОООООО
ОООООО
ОООООО
ОООООО
ОООООО
Coefficients, h[k]
k = 0..N
Data memory
(FIR/COR)
Program memory (FIRK/CORK)
sample_buf
coeff_array
ACr+1
ACr+2
ACr
y =
For COR/CORK
ACr
ACr+1
y =
For FIR/FIRK
TAG=1 for 2
nd
to last sample for
Circular buffer operation
+
Accumulators Pointer
Point to accumulator, ACr
An = ACn
Circular buffer operation only
Circular buffer length, –2N
R5
sample_buf address
Rx
even
{R0,R2,R4,R6}
coeff_array address
DP
coeff_array address
Rx
even
+1
{R1,R3,R5,R7}
FIR/COR only
FIRK/CORK only
† The value of y is stored in ACr and ACr+1 for FIR instruction (32-bit accumulation). COR instruction uses 48-bit accumulation
and includes accumulator ACr+2.
coeff_array
Coefficients, h[k]
k = 0..N