System Overview
Am186™CC/CH/CU Microcontrollers User’s Manual
3-21
PROGRAMMABLE I/O (PIOS)
PIO47–PIO0
(For a list of the
multiplexed
signals ordered
by PIO number,
see Table 3-2.)
B
Shared Programmable I/O pins can be programmed with the
following attributes: PIO function (enabled/disabled), direction
(input/output), and weak pullup or pulldown.
After a reset, the PIO pins default to various configurations. Most
of the PIO pins are configured as PIO inputs with pullup after
reset. The system initialization code must reconfigure any PIO
pins as required.
PIO5, PIO15, PIO27, PIO29, PIO30, and PIO33–PIO35 are
capable of generating an interrupt on the shared interrupt
channel 14.
The multiplexed signals PIO8/ARDY, PIO13/PCS0,
PIO14/PCS1, PIO15/WR, PIO29/DT/R, PIO30/DEN,
PIO33/ALE, PIO34/BHE, and PIO35/SRDY default to non-PIO
operation at reset.
The following PIO signals are multiplexed with alternate signals
that can be used by emulators: PIO8, PIO15, PIO33, PIO34, and
PIO35. Consider any emulator requirements for the alternate
signals before using these pins as PIOs.
PROGRAMMABLE TIMERS
[PWD]
[INT8]
PIO6
STI
Pulse-Width Demodulator: If pulse-width demodulation is
enabled, [PWD] processes a signal through the Schmitt trigger
input. [PWD] is used internally to drive [TMRIN0] and [INT8], and
[PWD] is inverted internally to drive [TMRIN1] and an additional
internal interrupt. If interrupts are enabled and Timer 0 and Timer
1 are properly configured, the pulse width of the alternating
[PWD] signal can be calculated by comparing the values in Timer
0 and Timer 1.
In PWD mode, the signals [TMRIN0]/PIO27 and [TMRIN1]/PIO0
can be used as PIOs. If they are not used as PIOs they are
ignored internally.
The additional internal interrupt used in PWD mode uses the
same interrupt channel as [INT7]. If [INT7] is used, it must be
assigned to the shared interrupt channel.
Table 3-7
Signal Descriptions (Continued)
Signal Name
1
Multiplexed
Signal(s)
Type Description
Summary of Contents for Am186 CC
Page 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Page 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Page 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Page 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Page 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Page 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Page 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Page 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Page 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Page 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Page 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Page 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Page 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...