Modular Input/Output Subsystem (MIOS14)
MPC561/MPC563 Reference Manual, Rev. 1.2
17-28
Freescale Semiconductor
17.9.1.1
MDASM Signal Functions
The MDASM has one dedicated external signal. This signal is used in input or in output depending on the
selected mode. When in input, it allows the MDASM to perform input capture, input pulse width
measurement and input period measurement. When in output, it allows output compare, single shot output
pulse, single output compare and output port bit operations as well as output pulse width modulation.
NOTE
In disable mode, the 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.
17.9.2
MDASM Description
The MDASM contains two timing channels A and B associated with the same input/output signal. The
dual action submodule is so called because its timing channel configuration allows two events (input
capture or output compare) to occur before software intervention is required.
Six operating modes allow the software to use the MDASM’s input capture and output compare functions
to perform pulse width measurement, period measurement, single pulse generation and continuous pulse
width generation, as well as standard input capture and output compare. The MDASM can also work as a
single I/O signal. See
for details.
Channel A comprises one 16-bit data register and one 16-bit comparator. Channel B also consists of one
16-bit data register and one 16-bit comparator, however, internally, channel B has two data registers B1
and B2, and the operating mode determines which register is accessed by the software:
•
In the input modes (IPWM, IPM and IC), registers A and B2 are used to hold the captured values;
in these modes, the B1 register is used as a temporary latch for channel B.
•
In the output compare modes (OCB and OCAB), registers A and B2 are used to define the output
pulse; register B1 is not used in these modes.
•
In the output pulse width modulation mode (OPWM), registers A and B1 are used as primary
registers and hidden register B2 is used as a double buffer for channel B.
Register contents are always transferred automatically at the correct time so that the minimum pulse
(measurement or generation) is just one 16-bit counter bus count. The A and B data registers are always
read/write registers, accessible via the MIOB.
In the input modes, the edge detect circuitry triggers a capture whenever a rising or falling edge (as defined
by the EDPOL bit) is applied to the input signal. The signal on the input signal is Schmitt triggered and
synchronized with the MIOS14 CLOCK.
In the disable mode (DIS) and in the input modes, the PIN bit reflects the state present on the input signal
(after being Schmitt triggered and synchronized). In the output modes the PIN bit reflects the value present
on the output flip-flop. The output flip-flop is used in output modes to hold the logic level applied to the
output signal.
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...
