9-24
DSP56309UM/D MOTOROLA
Triple Timer Module
Timer Operational Modes
9.4.3
Pulse Width Modulation (PWM, Mode 7)
In this mode, the timer generates periodic pulses of a preset width.
Set the TE bit to clear the counter and enable the timer. The value to which the timer is to
count is loaded into the TPCR. When first timer clock is received from either the
DSP56309 internal clock divided by two (CLK/2) or the prescaler clock output, the
counter is loaded with the TLR value. Each subsequent timer clock increments the
counter.
When the counter equals the value in the TCPR, the TIO output signal is toggled and the
TCF bit in the TCSR is set. The contents of the counter are placed into the TCR. If the
TCIE bit is set, a compare interrupt is generated. The counter continues to be
incremented on each timer clock.
If counter overflow has occurred, the TIO output signal is toggled, the TOF bit in TCSR
is set, and an overflow interrupt is generated if the TOIE bit is set. If the TRM bit is set,
the counter is loaded with the TLR value on the next timer clock and the count is
resumed. If the TRM bit is cleared, the counter continues to be incremented on each
timer clock.
This process is repeated until the timer is disabled by clearing the TE bit.
TIO signal polarity is determined by the value of the INV bit. When the counter is
started by setting the TE bit, the TIO signal assumes the value of the INV bit. On each
subsequent toggling of the TIO signal, the polarity of the TIO signal is reversed. For
example, if the INV bit is set, the TIO signal generates the following signal: 1010. If the
INV bit is cleared, the TIO signal generates the following signal: 0101.
The counter contents can be read at any time by reading the TCR.
The value of the TLR determines the output period ($FFFFFF
-
TLR + 1). The timer
counter increments the initial TLR value and toggles the TIO signal when the counter
value exceeds $FFFFFF.
Bit Settings
Mode Characteristics
TC3
TC2
TC1
TC0
Mode
Name
Function
TIO
Clock
0
1
1
1
7
Pulse Width
Modulation
PWM
Output
Internal
Summary of Contents for DSP56309
Page 25: ...xxii DSP56309UM D MOTOROLA Figure D 25 Port E Registers PCRE PRRE PDRE D 39 ...
Page 30: ...MOTOROLA DSP56309UM D 1 1 SECTION 1 DSP56309 OVERVIEW ...
Page 47: ...1 18 DSP56309UM D MOTOROLA DSP56309 Overview DSP56309 Architecture Overview ...
Page 48: ...MOTOROLA DSP56309UM D 2 1 SECTION 2 SIGNAL CONNECTION DESCRIPTIONS ...
Page 85: ...2 38 DSP56309UM D MOTOROLA Signal Connection Descriptions OnCE JTAG Interface ...
Page 86: ...MOTOROLA DSP56309UM D 3 1 SECTION 3 MEMORY CONFIGURATION ...
Page 104: ...MOTOROLA DSP56309UM D 4 1 SECTION 4 CORE CONFIGURATION ...
Page 124: ...MOTOROLA DSP56309UM D 5 1 SECTION 5 GENERAL PURPOSE I O ...
Page 125: ...5 2 DSP56309UM D MOTOROLA General Purpose I O 5 1 INTRODUCTION 5 3 5 2 PROGRAMMING MODEL 5 3 ...
Page 128: ...MOTOROLA DSP56309UM D 6 1 SECTION 6 HOST INTERFACE HI08 ...
Page 166: ...MOTOROLA DSP56309UM D 7 1 SECTION 7 ENHANCED SYNCHRONOUS SERIAL INTERFACE ESSI ...
Page 212: ...MOTOROLA DSP56309UM D 8 1 SECTION 8 SERIAL COMMUNICATION INTERFACE SCI ...
Page 241: ...8 30 DSP56309UM D MOTOROLA Serial Communication Interface SCI GPIO Signals and Registers ...
Page 242: ...MOTOROLA DSP56309UM D 9 1 SECTION 9 TRIPLE TIMER MODULE ...
Page 269: ...9 28 DSP56309UM D MOTOROLA Triple Timer Module Timer Operational Modes ...
Page 270: ...MOTOROLA DSP56309UM D 10 1 SECTION 10 ON CHIP EMULATION MODULE ...
Page 302: ...MOTOROLA DSP56309UM D 11 1 SECTION 11 JTAG PORT ...
Page 369: ...C 22 DSP56309UM D MOTOROLA DSP56309 BSDL Listing ...
Page 370: ...MOTOROLA DSP56309UM D D 1 APPENDIX D PROGRAMMING REFERENCE ...
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