QADC64E Enhanced Mode Operation
MPC561/MPC563 Reference Manual, Rev. 1.2
14-66
Freescale Semiconductor
Each port A or B signal is configured as an input or output by programming the port data direction register
(DDRQA or DDRQB). The digital input signal states are read by the software in the upper half of the port
data register when the port data direction register specifies that the signals are inputs. The digital data in
the port data register is driven onto the port A or B signals when the corresponding bit in the port data
direction register specifies output. Refer to
Appendix B, “Internal Memory Map
” for more information.
Since the outputs are configured as push-pull drivers, external pull-up provisions are not necessary when
the output is used to drive another integrated circuit.
14.6.2
External Trigger Input Signals
The QADC64E uses two external trigger signals (ETRIG[2:1]). Each of the two input external trigger
signals is associated with one of the scan queues, queue 1 or queue 2 The assignment of ETRIG[2:1] to a
queue is made in the QACR0 register by the TRG bit. When TRG=0, ETRIG1 triggers queue 1 and
ETRIG2 triggers queue 2. When TRG=1, ETRIG1 triggers queue 2 and ETRIG2 triggers queue 1.
14.6.3
Analog Power Signals
V
DDA
and V
SSA
signals supply power to the analog subsystems of the QADC64E module. Dedicated
power is required to isolate the sensitive analog circuitry from the normal levels of noise present on the
digital power supply. Refer to
Appendix F, “Electrical Characteristics
,” for more information.
The analog supply signals (V
DDA
and V
SSA
) define the limits of the analog reference voltages (V
RH
and
V
RL
) and of the analog multiplexer inputs.
is a diagram of the analog input circuitry.
Figure 14-47. Equivalent Analog Input Circuitry
SAMPLE
AMP
16 CHANNELS
V
SSA
V
RL
V
DDA
QADC64E 16CH SAMPLE AMP
V
RH
S/H
RC DAC
Comparator
C
P
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...