
2.4 IIR Filter DSP Unit
79
2.4 IIR Filter DSP Unit
This DSP unit provides hardware calculation of sum-of-products calculations (
ΣBi*Yj + ΣAm*Xn). It can
be used for fast, easy IIR filter calculations.
Features
Coefficients A and B, and variables X and Y are 16-bits x 4 banks.
The number of products can be selected in the range (1 to 4) + (1 to 4).
Rounding and clipping functions can be selected at 10-bit or 12-bit length.
Multiple banks can be linked, allowing results of calculations to be transferred into registers in the next
bank.
Calculation time is (M+N+1) x B + 1 machine cycles (where M, N=number of products, B=number of
banks).
2.4.1 Register List
Fig. 2.4.1 DSP Unit Registers
Note:
Addresses in registers X and Y are valid only for reading. Write operations are directed to the 0 reg-
isters regardless of address within banks.
00 0080H
00 0082H
00 0084H
00 0086H
00 0088H
Address
15
0
Product control/status
Reserved
Sum-of-products calculation
Sum-of-products output
register MCSR
continuous control register MCCR
register MDOR
MDORL
MDORM
MDORH
00 1940H
AX0
00 1942H
AX1
00 1944H
AX2
00 1946H
AX3
Status register X
00 1960H
AY0
00 1962H
AY1
00 1964H
AY2
00 1966H
AY3
Status register Y
00 1920H
AB0
00 1922H
AB1
00 1924H
AB2
00 1926H
AB3
Coefficient RAM B
00 1900H
AA0
00 1902H
AA1
00 1904H
AA2
00 1906H
AA3
Coefficient RAM A
Bank A
00 1948 H
BX0
00 194AH
BX1
00 194CH
BX2
00 194EH
BX3
Status register X
00 1968 H
BY0
00 196AH
BY1
00 196CH
BY2
00 196EH
BY3
Status register Y
00 1928 H
BB0
00 192AH
BB1
00 192CH
BB2
00 192EH
BB3
Coefficient RAM B
00 1908 H
BA0
00 190AH
BA1
00 190CH
BA2
00 190EH
BA3
Coefficient RAM A
Bank B
00 1950H
CX0
00 1952H
CX1
00 1954H
CX2
00 1956H
CX3
Status register X
00 1970H
CY0
00 1972H
CY1
00 1974H
CY2
00 1976H
CY3
Results register Y
00 1930H
CB0
00 1932H
CB1
00 1934H
CB2
00 1936H
CB3
Coefficient RAM B
00 1910H
CA0
00 1912H
CA1
00 1914H
CA2
00 1916H
CA3
Coefficient RAM A
Bank C
00 1958 H
DX0
00 195AH
DX1
00 195CH
DX2
00 195EH
DX3
Status register X
00 1978 H
DY0
00 197AH
DY1
00 197CH
DY2
00 197EH
DY3
Results register Y
00 1938 H
DB0
00 193AH
DB1
00 193CH
DB2
00 193EH
DB3
Coefficient RAM B
00 1918 H
DA0
00 191AH
DA1
00 191CH
DA2
00 191EH
DA3
Coefficient RAM A
Bank D