Modular Input/Output Subsystem (MIOS14)
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
17-29
The 16-bit counter bus selector is common to all input and output functions; it connects the MDASM to
one of the four 16-bit counter buses available to that submodule instance and is controlled in software by
the 16-bit counter bus selector bits BSL0 and BSL1 in the MDASMSCR register.
17.9.3
MDASM Modes of Operation
The mode of operation of the MDASM is determined by the mode select bits MODE[0:3] in the
MDASMSCR register (see
To avoid spurious interrupts, and to make sure that the FLAG line is activated according to the newly
selected mode, the following sequence of operations should be adopted when changing mode:
1. Disable MDASM interrupts (by resetting the enable bit in the relevant MIRSM)
2. Change mode (via disable mode)
3. Reset the corresponding FLAG bit in the relevant MIRSM
4. Re-enable MDASM interrupts (if desired)
NOTE
When changing between output modes, it is not necessary to follow this
procedure, as in these modes the FLAG bit merely indicates to the software
that the compare value can be updated. However changing modes without
passing via the disable mode does not guarantee the subsequent
functionality.
17.9.3.1
Disable (DIS) Mode
The disable mode is selected by setting MODE[0:3] to 0b0000.
In this mode, all input capture and output compare functions of the MDASM are disabled and the FLAG
line is maintained inactive, but the input port signal function remains available. The associated signal
becomes a high impedance input and the input level on this signal is reflected by the state of the PIN bit
in the MDASMSCR register. All control bits remain accessible, allowing the software to prepare for future
Table 17-16. MDASM Modes of Operation
MODE[0:3]
Mode
Description of Mode
0000
DIS
Disabled — Input signal is high impedance; PIN gives state of the input signal.
0001
IPWM
Input pulse width measurement — Capture on the leading edge and the trailing edge of an input pulse.
0010
IPM
Input period measurement — Capture two consecutive rising/falling edges.
0011
IC
Input capture — Capture when the designated edge is detected.
0100
OCB
Output compare, flag line activated on B compare — Generate leading and trailing edges of an output
pulse.
0101
OCAB
Output compare, flag line activated on A and B compare — Generate leading and trailing edges of an
output pulse.
1xxx
OPWM
Output pulse width modulation — Generate continuous PWM output with 7, 9, 11, 12, 13, 14, 15 or 16
bits of resolution.
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...