Motorola ColdFire MCF5281 - Manual (Page 542)

Queued Analog-to-Digital Converter (QADC)
28-4 Freescale Semiconductor
28.4.1.1 Port QA Analog Input Signals
When used as analog inputs, the four port QA signals are referred to as AN[56:55, 53:52].
Figure 28-2. QADC Input and Output Signals
28.4.1.2 Port QA Digital Input/Output Signals
Port QA signals are referred to as PQA[4:3, 1:0] when used as a bidirectional 4-bit digital input/output
port. These four signals may be used for general-purpose digital input or digital output.
Port QA signals are connected to a digital input synchronizer during reads and may be used as
general-purpose digital inputs when the applied voltages meet high-voltage input (V
IH
) and low-voltage
input (V
IL
) requirements.
Each port QA signal is configured as an input or output by programming the port data direction register
(DDRQA). The digital input signal states are read from the port QA data register (PORTQA) when
DDRQA specifies that the signals are inputs. The digital data in PORTQA is driven onto the port QA
signals when the corresponding bits in DDRQA specify output. See
Section 28.6.4, “Port QA and QB Data
Direction Register (DDRQA & DDRQB) .
28.4.2 Port QB Signal Functions
The four port QB signals can be used as analog inputs or as a 4-bit digital I/O port.
28.4.2.1 Port QB Analog Input Signals
When used as analog inputs, the four port QB signals are referred to as AN[3:0].
AN52/MA0/PQA0
AN53/MA1/PQA1
AN55/ETRIG1/PQA3
AN56/ETRIG2/PQA4
AN0/ANW/PQB0
AN1/ANX/PQB1
AN2/ANY/PQB2
AN3/ANZ/PQB3
Digital
Analog
V
SSI
Analog Power and Ground
Internal Digital Power
POR
T
QB
Converter
Results
and
Control
Analog
Mux and
Port QB Analog Inputs
External MUX Inputs
Digital Inputs
Port QA Analog Inputs
External Trigger Inputs
External MUX Address Outputs
V
DDI
V
SSA
V
DDA
V
RH
V
RL
Analog References
Shared with Other Modules
Digital I/O
Port Logic
POR
T
Q
A
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3