20-101-0520 Rabbit Semiconductor, 20-101-0520 Datasheet - Page 86
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20-101-0520
Manufacturer Part Number
20-101-0520
Description
MODULE RABBITCORE RCM3200
Manufacturer
Rabbit Semiconductor
Datasheet
1.20-101-0522.pdf
(96 pages)
Specifications of 20-101-0520
Module/board Type
MPU Core Module
Product
Microcontroller Modules
Core Processor
Rabbit 3000
Clock Speed
44.2 MHz
Interface Type
Ethernet, Serial
Flash
512 KB
Timers
10 x 8 bit, 1 x 10 bit
Operating Supply Voltage
3.15 V to 3.45 V
Board Size
69 mm x 47 mm x 22 mm
Core
RCM3200
Processor Series
RCM3200
For Use With/related Products
RCM3200
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Other names
316-1097
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Company:
Part Number:
20-101-0520
Manufacturer:
Rabbit Semiconductor
Quantity:
1 879
F.4 PWM Outputs
The Pulse-Width Modulator consists of a 10-bit free-running counter and four width regis-
ters. Each PWM output is high for n + 1 counts out of the 1024-clock count cycle, where n
is the value held in the width register. The PWM output high time can optionally be spread
throughout the cycle to reduce ripple on the externally filtered PWM output. The PWM is
clocked by the output of Timer A9. The spreading function is implemented by dividing
each 1024-clock cycle into four quadrants of 256 clocks each. Within each quadrant, the
Pulse-Width Modulator uses the eight MSBs of each pulse-width register to select the base
width in each of the quadrants. This is the equivalent to dividing the contents of the pulse-
width register by four and using this value in each quadrant. To get the exact high time, the
Pulse-Width Modulator uses the two LSBs of the pulse-width register to modify the high
time in each quadrant according to Table F-3 below. The “n/4” term is the base count, and
is formed from the eight MSBs of the pulse-width register.
The diagram below shows a PWM output for several different width values for both
modes of operation. Operation in the spread mode reduces the filtering requirements on
the PWM output in most cases.
82
n=255, normal
n=259, normal
n=255, spread
n=258, spread
n=256, spread
n=257, spread
n=259, spread
00
01
10
11
Pulse Width LSBs
Figure F-1. PWM Outputs for Various Normal and Spread Modes
(64 counts)
(65 counts)
(65 counts)
(65 counts)
(65 counts)
n/4 + 1
n/4 + 1
n/4 + 1
n/4 + 1
Table F-3. PWM Outputs
1st
(260 counts)
(256 counts)
(64 counts)
(64 counts)
(64 counts
(65 counts)
(65 counts)
n/4
n/4
n/4 + 1
n/4 + 1
)
2nd
(64 counts)
(64 counts
(65 counts)
(65 counts)
(65 counts)
n/4
n/4 + 1
n/4 + 1
n/4 + 1
3rd
)
RabbitCore RCM3200
(64 counts)
(64 counts)
(64 counts)
(64 counts)
n/4
n/4
n/4
n/4 + 1
(65 counts)
4th