SAB-C165 SIEMENS [Siemens Semiconductor Group], SAB-C165 Datasheet - Page 19

• Manufacturer Part Number: SAB-C165
• Description: C16x-Family of High-Performance CMOS 16-Bit Microcontrollers
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

C165
Figure 7
Block Diagram of GPT2
Parallel Ports
The C165 provides up to 77 I/O lines which are organized into six input/output ports and one input
port. All port lines are bit-addressable, and all input/output lines are individually (bit-wise)
programmable as inputs or outputs via direction registers. The I/O ports are true bidirectional ports
which are switched to high impedance state when configured as inputs. The output drivers of three
I/O ports can be configured (pin by pin) for push/pull operation or open-drain operation via control
registers. During the internal reset, all port pins are configured as inputs.
All port lines have programmable alternate input or output functions associated with them. PORT0
and PORT1 may be used as address and data lines when accessing external memory, while Port
4 outputs the additional segment address bits A23/19/17...A16 in systems where segmentation is
enabled to access more than 64 KBytes of memory. Port 6 provides optional bus arbitration signals
(BREQ, HLDA, HOLD) and chip select signals. Port 3 includes alternate functions of timers, serial
interfaces, the optional bus control signal BHE and the system clock output (CLKOUT). Port 5 is
used for timer control signals. All port lines that are not used for these alternate functions may be
used as general purpose I/O lines.
Semiconductor Group
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