JAJSLP2A august 2021 – july 2023 AFE439A2 , AFE539A4 , AFE639D2
PRODUCTION DATA
The AFE439A2 provides a 7-bit duty-cycle PWM output on the SDA/SCLK/PWM pin. Pull the VREF/MODE pin high to enable PWM functionality. Table 7-3 lists all the possible PWM frequency configurations.
SRAM REGISTER | PWM-FREQUENCY | PWM FREQUENCY (kHz) | DUTY CYCLE (%) FOR CODE 1 | DUTY CYCLE (%) FOR CODE 126 |
---|---|---|---|---|
PWM-FREQUENCY (0x21[4:0])(1) | 0 | Invalid | N/A | N/A |
1 | 48.828 | 4.88 | 95.12 | |
2 | 24.414 | 2.44 | 97.56 | |
3 | 16.276 | 1.63 | 98.37 | |
4 | 12.207 | 1.22 | 98.44 | |
5 | 8.138 | 0.81 | 98.44 | |
6 | 6.104 | 0.78 | 98.44 | |
7 | 3.052 | 0.78 | 98.44 | |
8 | 2.035 | 0.78 | 98.44 | |
9 | 1.526 | 0.78 | 98.44 | |
10 | 1.221 | 0.78 | 98.44 | |
11 | 1.017 | 0.78 | 98.44 | |
12 | 0.872 | 0.78 | 98.44 | |
13 | 0.763 | 0.78 | 98.44 | |
14 | 0.678 | 0.78 | 98.44 | |
15 | 0.610 | 0.78 | 98.44 | |
16 | 0.555 | 0.78 | 98.44 | |
17 | 0.509 | 0.78 | 98.44 | |
18 | 0.470 | 0.78 | 98.44 | |
19 | 0.436 | 0.78 | 98.44 | |
20 | 0.407 | 0.78 | 98.44 | |
21 | 0.381 | 0.78 | 98.44 | |
22 | 0.359 | 0.78 | 98.44 | |
23 | 0.339 | 0.78 | 98.44 | |
24 | 0.321 | 0.78 | 98.44 | |
25 | 0.305 | 0.78 | 98.44 | |
26 | 0.291 | 0.78 | 98.44 | |
27 | 0.277 | 0.78 | 98.44 | |
28 | 0.265 | 0.78 | 98.44 | |
29 | 0.254 | 0.78 | 98.44 | |
30 | 0.244 | 0.78 | 98.44 | |
31 | 0.218 | 0.78 | 98.44 |
The duty cycle of the PWM is proportional to the 7-bit code, 0d to 126d. As Table 7-4 shows, the code 127d corresponds to 100% duty cycle. The duty cycle 99.22% (127d/128d) is skipped to achieve 100% duty cycle using a 7-bit code. The PWM duty-cycle setting is done by the state machine and is not exposed to the user.
CODE | DUTY-CYCLE | DESCRIPTION |
---|---|---|
0 | 0% | Always 0 |
1 | 0.78% | Minimum linear duty cycle |
x | (x/128)% | x is the code between 2d and 125d, both included. |
126 | 98.44% | Maximum linear duty cycle |
127 | 100% | Always 1. The duty cycle 99.22% (127d/128d) is skipped. |