Functional Description
14-24
ADSP-BF50x Blackfin Processor Hardware Reference
Effective PWM Accuracy
The PWM Controller has 16-bit resolution, but accuracy depends on the
PWM period. In single-update mode, the same values of
PWM_CHA
,
PWM_CHB
, and
PWM_CHC
define the on-times in both half cycles of the PWM
period. As a result, the effective accuracy of the PWM generation process
is 2
t
SCLK
(20 ns for a 100 MHz f
SCLK
). Incrementing one of the duty
cycle registers by 1 changes the resultant on-time of the associated PWM
signals by t
SCLK
in each half period (2
t
SCLK
for the full period). In dou-
ble-update mode, improved accuracy is possible since different values of
the duty cycles registers are used to specify the on-times in both the first
half and second half of the PWM period. As a result, it is possible to
adjust the on-time over the entire period in increments of t
SCLK
. This cor-
responds to an effective PWM accuracy of t
SCLK
in double-update mode
(10 ns for a 100 MHz f
SCLK
). The minimum achievable PWM switching
frequency at a given PWM accuracy is shown in
Table 14-1
for
SCLK
= 100 MHz.
Table 14-1. Minimum Achievable PWM Frequency versus
Bit Resolution for SCLK = 100 MHz
Resolution (bits)
PWM Frequency (kHz) in
Single-Update Mode
PWM Frequency (kHz) in
Double-Update Mode
8
195.3
390.6
9
97.7
195.3
10
48.8
97.7
11
24.4
48.8
12
12.2
24.4
13
6.1
12.2
14
3.05
6.1
Summary of Contents for EZ-KIT Lite ADSP-BF506F
Page 50: ...Contents l ADSP BF50x Blackfin Processor Hardware Reference ...
Page 92: ...Development Tools 1 30 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 110: ...Interface Overview 3 12 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 236: ...Internal Flash Memory Control Registers 6 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 650: ...Programming Examples 15 56 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 804: ...Programming Examples 17 92 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1194: ...Programming Examples 24 90 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1256: ...ACM Registers A 50 ADSP BF50x Blackfin Processor Hardware Reference ...
Page 1264: ...Boundary Scan Architecture B 8 ADSP BF50x Blackfin Processor Hardware Reference ...