Special Filter Instructions
4-63
Assembly Language Instructions
mov
A0,*nextSample
;Replace last sample with newest
sample
mov
*R0,A0
; and update the start of the
mov
*startOfBuff,R0
; circular buffer to here (R0)
First, the overflow mode must be reset. Next, R5 must be loaded with the
wrap
around value of the circular buffer. Wrap around happens automatically. This
tells the processor how many words to step back when the end of the circular
buffer is reached. This value must be negative and equal to N words even
though the buffer is N+1 words long. For example, suppose a four word circular
buffer starts at RAM location 0x0100 and ends at 0x0106 (N = 3). In order to
wrap around from location 0x0106 back to location 0x0100, the value 0x006
must be subtracted from 0x0106, giving 0x0100.
0x0100
TAGGED LOCATION
0x0106
0x0104
0x0102
Go back N words to
wrap around
R0 must point to the current starting point of the circular buffer. R1 must point
to the filter coefficients. The MR register must contain the first filter coefficient,
h[0]. R0 and R1 must be used this way. The filtering operation will not work if
the R
x registers are reversed. The following are the only allowable register
combinations,
R0 points to circular buffer and R1 points to filter coefficients
R2 points to circular buffer and R3 points to filter coefficients
Summary of Contents for MSP50C614
Page 1: ...MSP50C614 Mixed Signal Processor User s Guide SPSU014 January 2000 Printed on Recycled Paper ...
Page 6: ...vi ...
Page 92: ...3 22 ...
Page 300: ...Instruction Set Summay 4 208 Assembly Language Instructions ...
Page 314: ...Software Emulator 5 14 Figure 5 13 Project Menu Figure 5 14 Project Open Dialog ...
Page 325: ...Software Emulator 5 25 Code Development Tools Figure 5 25 EPROM Programming Dialog ...
Page 331: ...Software Emulator 5 31 Code Development Tools Figure 5 31 Context Sensitive Help System ...
Page 368: ...5 68 ...
Page 394: ...7 12 ...
Page 402: ...A 8 ...
Page 412: ...Packaging B 10 ...