Architectural Overview
1-10
Am186™CC/CH/CU Microcontrollers User’s Manual
The Am186CH HDLC microcontroller has 14 internal maskable interrupt sources.
The Am186CU USB microcontroller has 13 internal maskable interrupt sources.
In addition to interrupts managed by the interrupt controller, each microcontroller supports
eight nonmaskable interrupts—an external or internal nonmaskable interrupt (NMI), a trace
interrupt, and software interrupts and exceptions.
1.4.3.2
General-Purpose DMA Channels (Chapter 8)
Four of the DMA channels in each of the Am186CC/CH/CU microcontrollers are general
purpose. The general-purpose DMA channels support data transfer between memory and
I/O spaces (i.e., memory-to-I/O or I/O-to-memory) or within the same space (i.e., memory-
to-memory or I/O-to-I/O). In addition, the microcontrollers support data transfer between
peripherals and memory or I/O. Internal peripherals that support general-purpose DMA are
Timer 2, which can provide a periodic internal DMA request, and the two asynchronous
serial ports (UART and High-Speed UART).
External peripherals support DMA transfers through the external DMA request pins (DRQ1–
DRQ0). Each general-purpose channel accepts a DMA request from one of three sources:
the DMA request signals (DRQ1–DRQ0), Timer 2, or the UARTs. (Note that Timer 2 acts
only as a DMA request source; no data is transferred to or from Timer 2.) In addition to the
general-purpose channels, the microcontrollers provide SmartDMA channels (see
“SmartDMA Channels (Chapter 8)” on page 1-8).
The USB peripheral controller in the Am186CC and Am186CU microcontrollers can also
request a general-purpose DMA transfer.
1.4.3.3
Programmable I/O Signals (Chapter 9)
Each of the Am186CC/CH/CU microcontrollers provides 48 user-programmable input/
output signals (PIOs). In the Am186CC microcontroller, each of these signals shares a pin
with at least one alternate function. In the Am186CH and Am186CU microcontrollers, most
but not all of the PIOs share a pin with alternate functions. If an application does not need
the alternate function, the associated PIO can be used by programming the PIO registers.
If a pin is enabled to function as a PIO signal, the alternate function is disabled and does
not affect the pin. A PIO signal can operate as an input or output, with or without internal
pullup or pulldown resistors (whether the resistors are pullup or pulldown depends on the
pin configuration and is not user-configurable), or as an open-drain output. In addition to
the three PIOs multiplexed with interrupt signals, eight other PIOs can be configured as
external interrupt sources. For more information about PIOs as interrupt sources, see
Chapter 7, “Interrupts.”
1.4.3.4
Programmable Timers (Chapter 10)
Each of the Am186CC/CH/CU microcontrollers has three 16-bit programmable timers.
Timers 0 and 1 are highly versatile and are each connected to two external pins (each one
has an input and an output). These two timers can count or time external events that drive
the timer input pins. Timers 0 and 1 can also generate nonrepetitive or variable-duty-cycle
waveforms on the timer output pins.
Timer 2 is not connected to any external pins. Software can use it to generate interrupts,
or poll it for real-time coding and time-delay applications. Software can also use Timer 2
as a prescaler to Timer 0 and Timer 1, or as a DMA request source (see Chapter 8, “DMA
Controller”).
The source clock for Timer 2 is one-fourth of the CPU clock frequency. Timers 0 and 1 can
use every fourth cycle of the CPU clock as a source, or they can be driven from the timer
CH
CU
CC
CU
Содержание Am186 CC
Страница 1: ...Am186 CC CH CU Microcontrollers User s Manual Order 21914B...
Страница 4: ...iv Am186 CC CH CU Microcontrollers User s Manual...
Страница 18: ...Table of Contents xviii Am186 CC CH CU Microcontrollers User s Manual...
Страница 24: ...Introduction xxiv Am186 CC CH CU Microcontrollers User s Manual...
Страница 39: ...Architectural Overview Am186 CC CH CU Microcontrollers User s Manual 1 15 Figure 1 6 32 Channel Linecard CH CC...
Страница 40: ...Architectural Overview 1 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 86: ...System Overview 3 36 Am186 CC CH CU Microcontrollers User s Manual...
Страница 92: ...Emulator Support 4 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 112: ...DRAM Controller 6 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 134: ...Interrupts 7 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 186: ...Programmable I O Signals 9 8 Am186 CC CH CU Microcontrollers User s Manual...
Страница 200: ...Watchdog Timer 11 6 Am186 CC CH CU Microcontrollers User s Manual...
Страница 232: ...Asynchronous Serial Ports UARTs 13 24 Am186 CC CH CU Microcontrollers User s Manual...
Страница 242: ...Synchronous Serial Port SSI 14 10 Am186 CC CH CU Microcontrollers User s Manual...
Страница 264: ...High Level Data Link Control HDLC 15 22 Am186 CC CH CU Microcontrollers User s Manual...
Страница 332: ...Universal Serial Bus USB 18 34 Am186 CC CH CU Microcontrollers User s Manual...
Страница 348: ...Register Summary A 16 Am186 CC CH CU Microcontrollers User s Manual...
Страница 376: ...Index Index 18 Am186 CC CH CU Microcontrollers User s Manual...