Operating Modes
9
-8
DSP56303 User’s Manual
9.3.1.2 Timer Pulse (Mode 1)
In Mode 1, the timer generates an external pulse on its TIO signal when the timer count
reaches a pre-set value. The TIO signal is loaded with the value of the TCSR[INV] bit. When
the counter matches the TCPR value, TCSR[TCF] is set and a compare interrupt is generated
if the TCSR[TCIE] bit is set. The polarity of the TIO signal is inverted for one timer clock
period. If TCSR[TRM] is set, the counter is loaded with the TLR value on the next timer
clock and the count is resumed. If TCSR[TRM] is cleared, the counter continues to increment
on each timer clock. This process repeats until TCSR[TE] is cleared (disabling the timer).
The TLR value in the TCPR sets the delay between starting the timer and generating the
output pulse. To generate successive output pulses with a delay of X clock cycles between
signals, set the TLR value to X/2 and set the TCSR[TRM] bit. This process repeats until the
timer is disabled.
Bit Settings
Mode Characteristics
TC3
TC2
TC1
TC0
Mode
Name
Function
TIO
Clock
0
0
0
1
1
Timer Pulse
Timer
Output
Internal
Figure 9-5. Pulse Mode (TRM = 1)
Mode 1 (internal clock): TRM = 1
N = write preload
M = write compare
TE
Clock
(CLK/2 or prescale CLK)
TLR
TCPR
TCF (Compare Interrupt if TCIE = 1)
Counter (TCR)
first event
M
0
N
N + 1
M
N
N + 1
N
pulse width =
timer clock
period
TIO pin (INV = 0)
TIO pin (INV = 1)
Summary of Contents for DSP56303
Page 1: ...DSP56303 User s Manual 24 Bit Digital Signal Processor DSP56303UM AD Revision 1 January 2001 ...
Page 52: ...JTAG OnCE Interface 2 22 DSP56303 User s Manual ...
Page 114: ...General Purpose Input Output GPIO 5 10 DSP56303 User s Manual ...
Page 212: ...GPIO Signals and Registers 8 26 DSP56303 User s Manual ...
Page 268: ...Interrupt Equates A 22 DSP56303 User s Manual ...
Page 306: ...Programming Sheets B 38 DSP56303 User s Manual ...
Page 320: ...Index 14 DSP56303 User s Manual ...