Datasheet

Theory of operation STPMC1
38/77 Doc ID 15728 Rev 7
The ACR, ACS and ACT registers (bits [7:0], see paragraph 9.17.7) holds the information
needed for this calculation.
Let us indicate t
RS
, t
ST
, t
TR
, the delays between R, S and T phases. It is:
Equation 1
t
RS
+ t
ST
+ t
TR
= T = 1 / ƒ
Concatenating ACT[7:0], ACS[7:0], ACR[7:0] bytes, two 12 bits vectors defined as below are
obtained:
ACT[7:0], ACS[7:0], ACR[7:0] = Asr[12, 10:0], Art[12, 10:0]
The delay times are calculated with the following formulas:
Equation 2
Equation 3
From
Equation 1 , Equation 2 and Equation 3 it is possible to retrieve phase delays t
RS
, t
ST
and t
TR
.
Figure 13. Phase delay
t
RS
t
RS
t
ST
t
ST
t
TR
t
TR
[] ()
[]
MCLK
12Asr
11
TRSTAsr
f
8
120:10Asrtttime ⋅
⎟
⎠
⎞
⎜
⎝
⎛
+−=−=
[] ()
[]
MCLK
12Art
11
STRSArt
f
8
120:10Arttttime ⋅
⎟
⎠
⎞
⎜
⎝
⎛
+−=−=