Table 104. Precision Vs. Number Of Iterations; Figure 37. Cordic Convergence For Square Root - ST STM32G4 Series Reference Manual

CORDIC co-processor (CORDIC)
Note: The convergence rate decreases as the quantization error starts to become significant.
The CORDIC can perform four iterations per clock cycle. For each function, the maximum
error remaining after every four iterations is shown in
clock cycles required to reach that precision. From this table, the desired number of cycles
can be determined and programmed in the PRECISION field of the CORDIC_CR register.
The co-processor will stop as soon as the programmed number of iterations has completed,
and the result can be read immediately.
Function
Sin, Cos,
(2)
Phase
Atan
436/2083

Figure 37. CORDIC convergence for square root

Table 104. Precision vs. number of iterations

Number of
iterations
4
8
12
, Mod,
16
(4)
20
24
Table
Number of
cycles
1
2
3
4
5
6
RM0440 Rev 1
104, together with the number of
Max residual error
q1.31 format q1.15 format
-3
2
-7
2
-11
2
-15
2
-18
2
-19
2
RM0440
(1)
-3
2
-7
2
-11
2
-15
2
-16
2
-16
2