1.3
Signal List
Package
D4/P3
Signal
Name
Description
Pin No.
Type
O/P
I/P
1
2
XTALN
The inverted output of the on-chip oscillator.
XTAL/CLOCK
The input to the on-chip oscillator, for external
Xtal circuit or clock.
3
4
5
6
D3
D2
D1
D0
O/P
O/P
O/P
O/P
D3, D2, D1 and D0 is a 4-bit parallel data word
output to the µController. The transmission of
data is under the control of the CSN input.
These 3-state outputs are held at high
impedance when CSN is at "1". See Bus Timing
Diagram (Figure 8).
If CSN is permanently at "0", D3, D2, D1 and D0
are permanently active. See Timing Diagram
(Figure 4 to 7).
7
8
CSN
I/P
The data output control function: this input is
provided by the µController. Data transfer
sequences are initiated, completed or aborted
by the CSN signal. See Bus Timing Diagram
(Figure 8).
IRQN
O/P
This output indicates an interrupt condition to
the µController by going to a logic "0". This is a
"wire-ORable" output, enabling the connection of
up to 8 peripherals to 1 interrupt port on the
µController. This pin has a low impedance
pulldown to logic "0" when active and a high-
impedance when inactive. An external pullup
resistor is required.
If CSN is permanently at "0", the interrupt
condition is a logic "0" pulse. See Timing
Diagram (Figure 4 to 7).
9
ENABLE
I/P
A low level input selects the powersave mode,
all circuits are reset and disabled. D0 - D3
outputs become high impedance. A high level
enables all circuits. (See also CSN).
ã 1999 Consumer Microcircuits Limited
4
D/663/3
CMLMICRO [ CML MICROCIRCUITS ]
