User’s Manual 99
9. PARALLEL PORTS
The Rabbit has five 8-bit parallel ports designated A, B, C, D and E. The pins used for the
parallel ports are also shared with numerous other functions as shown in Table 5-2. The
important properties of the ports are summarized below.
• Port A—Shared with the slave port data interface.
• Port B—Shared with control lines for slave port and clock I/O for clocked serial mode
option for serial ports A and B.
• Port C—Shared with serial port serial data I/O.
• Port D—4 bits shared with alternate I/O pins for serial ports A and B. 4 bits not shared.
Port D has the ability to configure its outputs as open drain outputs. Port D has output
preload registers that can be clocked into the output registers under timer control for
pulse generation. Port D bits 0–3 have a higher current drive capability.
• Port E—All bits of Port E can be configured as I/O strobes. 4 bits of port E can be used
as external interrupt inputs. One bit of port E is shared with the slave port chip select.
Port E has output preload registers that can be clocked into the output registers under
timer control for pulse generation.
To Next Page
Loading...
