122-32000 Parallax Inc, 122-32000 Datasheet - Page 204

• Manufacturer Part Number: 122-32000
• Description: MANUAL PROPELLER
• Manufacturer: Parallax Inc

Specifications of 122-32000

• Accessory Type: Manual
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: Propeller Education (PE) Kit
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

CTRA, CTRB
Counter A and Counter B Control Registers.
((PUB ┆ PRI))
((PUB ┆ PRI))
Returns: Current value of Counter A or Counter B Control Register, if used as a source
variable.
Explanation
CTRA
behavior of a cog’s Counter Modules. Each cog has two identical counter modules (A and B)
that can perform many repetitive tasks.
configuration settings of the Counter A and Counter B Modules, respectively.
The following discussion uses
register.
Each of the two counter modules can control or monitor up to two I/O pins and perform
conditional 32-bit accumulation of the value in the
every clock cycle. Each Counter Module has its own phase-locked loop (PLLx) which can be
used to synthesize frequencies from 64 MHz to 128 MHz.
With just a little configuration and in some cases a little maintenance from the cog, the
counter modules can be used for:
•
•
•
•
•
For some of these operations the cog can set the counter’s configuration, via
and it will perform its task completely independently. For others, the cog may use
time-align the counter’s reads and writes within a loop; creating the effect of a more complex
Page 204 · Propeller Manual v1.0
CTRA
CTRB
Frequency synthesis
Frequency measurement
Pulse counting
Pulse measurement
Multi-pin state measurement
and
CTRB
are two of six registers (
– Spin Language Reference
CTR
x,
FRQ
CTRA
x and
,
CTRB
PHS
The
x to refer to both the A and B pairs of each
,
•
•
•
•
•
FRQA
CTRA
FRQx
Pulse-width modulation (PWM)
Duty-cycle measurement
Digital-to-analog conversion (DAC)
Analog-to-digital conversion (ADC)
And more.
,
FRQB
and
register into the
,
PHSA
CTRB
, and
registers contain the
PHSB
PHSx
) that affect the
CTRA or CTRB
register on
WAITCNT
to
,