80C186EC/188EC, 80L186EC/188EC
272434 – 2
NOTE:
1. The LC network is only required when using a third overtone crystal.
Figure 2. 80C186EC Clock Connections
80C186EC PERIPHERAL
ARCHITECTURE
The 80C186EC integrates several common system
peripherals with a CPU core to create a compact, yet
powerful system. The integrated peripherals are de-
signed to be flexbile and provide logical interconnec-
tions between supporting units (e.g., the DMA unit
can accept requests from the Serial Communica-
tions Unit).
The list of integrated peripherals includes:
Ð Two cascaded, 8259A compatible, Programma-
ble Interrupt Controllers
Ð 3-Channel Timer/Counter Unit
Ð 2-Channel Serial Communications Unit
Ð 4-Channel DMA Unit
Ð 10-Output Chip-Select Unit
Ð 32-bit Watchdog Timer Unit
Ð I/O Port Unit
Ð Refresh Control Unit
Ð Power Management Unit
The registers associated with each integrated pe-
ripheral are contained within a 128 x 16-bit register
file called the Peripheral Control Block (PCB). The
base address of the PCB is programmable and can
be located on any 256 byte address boundary in ei-
ther memory or I/O space.
Figure 3 provides a list of the registers associated
with the PCB. The Register Bit Summary individually
lists all of the registers and identifies each of their
programming attributes.
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