52 Rabbit 2000 Microprocessor
5.3 Rabbit Pin Descriptions
Table 5-1 lists all the pins on the device, along with their direction, function, and pin num-
ber on the package.
Table 5-1. Rabbit Pin Descriptions
Pin Group Pin Name Direction Function Pin Numbers
Hardware
CLK Output
Peripheral clock output. This signal is
derived internally from the main system
oscillator as perclk, and may be divided
by 8, doubled, or both, by programmable
internal circuitry. This signal is enabled
after reset. Under program control, this pin
can output the full internal clock frequency,
or 1/2 the internal frequency, or it can be
used as a general-purpose output pin under
software control. See Table 7-3, “Global
Output Control Register (GOCR = 0x0E).”
1
/RESET Input Master reset. 37
XTALA1 Input
Quartz crystal for 32 kHz clock oscillator.
Lines to the crystal should be short and
shielded from crosstalk. If an external
clock is used, this pin should be driven by
the external clock.
40
XTALA2 Output
Quartz crystal for 32 kHz crystal oscillator.
Do not connect if an external clock is used.
41
XTALB1 Input
Quartz crystal for main system oscillator.
Lines to the crystal should be short and
shielded from crosstalk. If an external
clock is used this pin should be driven by
the external clock.
90
XTALB2 Output
Quartz crystal for main system oscillator.
Do not connect if an external clock is used.
91
CPU Buses
A0–A19 Output Address bus.
7, 17–20, 61–
68, 70–75, 79
D0–D7 Bidirectional Data bus. 9–16
Status/
Control
/WDTOUT Output
WDT timeout—outputs a pulse when the
internal watchdog times out. May also be
used to output a 30 µs pulse.
34
Status STATUS Output
Programmable for functions:
1. driven low on first opcode fetch cycle
2. driven low during interrupt
acknowledge cycle
3. to serve as a general-purpose output.
See Table 7-3, “Global Output Control
Register (GOCR = 0x0E).”.
38
To Next Page
Loading...
