cop8cde9 National Semiconductor Corporation, cop8cde9 Datasheet - Page 13

• Manufacturer Part Number: cop8cde9
• Description: 8-bit Cmos Flash Microcontroller With 8k Memory, Virtual Eeprom, 10-bit A/d And Brownout Reset
• Manufacturer: National Semiconductor Corporation

3.0 Pin Descriptions
CKI is the clock input. This can be connected (in conjunction
with CKO) to an external crystal circuit to form a crystal
oscillator. See Oscillator Description section.
RESET is the master reset input. See Reset description
section.
AV
connected to V
resistor ladder D/A converter used within the A/D converter.
AGND is the ground pin for the A/D converter. It should be
connected to GND externally. This is also the bottom of the
resistor ladder D/A converter used within the A/D converter.
The device contains up to six bidirectional 8-bit I/O ports (A,
B, G, H and L), where each individual bit may be indepen-
dently configured as an input (Schmitt trigger inputs on ports
L and G), output or TRI-STATE under program control. Three
data memory address locations are allocated for each of
these I/O ports. Each I/O port has three associated 8-bit
memory mapped registers, the CONFIGURATION register,
the output DATA register and the Pin input register. (See the
memory map for the various addresses associated with the
I/O ports.) Figure 3 shows the I/O port configurations. The
DATA and CONFIGURATION registers allow for each port bit
to be individually configured under software control as
shown below:
Port A is an 8-bit I/O port. All A pins have Schmitt triggers on
the inputs. The 44-pin package does not have a full 8-bit port
and contains some unbonded, floating pads internally on the
chip. The binary value read from these bits is undetermined.
The application software should mask out these unknown
bits when reading the Port A register, or use only bit-access
program instructions when accessing Port A. These uncon-
nected bits draw power only when they are addressed (i.e.,
in brief spikes). Additionally, if Port A is being used with some
combination of digital inputs and analog inputs, the analog
inputs will read as undetermined values and should be
masked out by software.
Port A supports the analog inputs for the A/D converter. Port
A has the following alternate pin functions:
A7 Analog Channel 7
A6 Analog Channel 6
A5 Analog Channel 5
A4 Analog Channel 4
A3 Analog Channel 3
A2 Analog Channel 2
A1 Analog Channel 1
A0 Analog Channel 0
Port B is an 8-bit I/O port. All B pins have Schmitt triggers on
the inputs. If Port B is being used with some combination of
digital inputs and analog inputs, the analog inputs will read
as undetermined values. The application software should
mask out these unknown bits when reading the Port B
register, or use only bit-access program instructions when
accessing Port B.
CONFIGURATION
CC
is the Analog Supply for A/D converter. It should be
Register
0
0
1
1
CC
externally. This is also the top of the
Register
DATA
0
1
0
1
Hi-Z Input
(TRI-STATE Output)
Input with Weak Pull-Up
Push-Pull Zero Output
Push-Pull One Output
(Continued)
Port Set-Up
13
Port B supports the analog inputs for the A/D converter. Port
B has the following alternate pin functions:
B7 Analog Channel 15 or A/D Input
B6 Analog Channel 14 or Analog Multiplexor Output
B5 Analog Channel 13 or Analog Multiplexor Output
B4 Analog Channel 12
B3 Analog Channel 11
B2 Analog Channel 10
B1 Analog Channel 9
B0 Analog Channel 8
Port G is an 8-bit port. Pin G0, G2–G5 are bi-directional I/O
ports. Pin G6 is always a general purpose Hi-Z input. All pins
have Schmitt Triggers on their inputs. Pin G1 serves as the
dedicated WATCHDOG output with weak pull-up if the
WATCHDOG feature is selected by the Option register.
The pin is a general purpose I/O if WATCHDOG feature is
not selected. If WATCHDOG feature is selected, bit 1 of the
Port G configuration and data register does not have any
effect on Pin G1 setup. G7 serves as the dedicated output
pin for the CKO clock output.
Since G6 is an input only pin and G7 is the dedicated CKO
clock output pin, the associated bits in the data and configu-
ration registers for G6 and G7 are used for special purpose
functions as outlined below. Reading the G6 and G7 data
bits will return zeros.
The device will be placed in the HALT mode by writing a “1”
to bit 7 of the Port G Data Register. Similarly the device will
be placed in the IDLE mode by writing a “1” to bit 6 of the
Port G Data Register.
Writing a “1” to bit 6 of the Port G Configuration Register
enables the MICROWIRE/PLUS to operate with the alter-
nate phase of the SK clock. The G7 configuration bit, if set
high, enables the clock start up delay after HALT when the
R/C clock configuration is used.
Port G has the following alternate features:
G7 CKO Oscillator dedicated output
G6 SI (MICROWIRE/PLUS Serial Data Input)
G5 SK (MICROWIRE/PLUS Serial Clock)
G4 SO (MICROWIRE/PLUS Serial Data Output)
G3 T1A (Timer T1 I/O)
G2 T1B (Timer T1 Capture Input)
G1 WDOUT WATCHDOG and/or Clock Monitor if WATCH-
G0 INTR (External Interrupt Input)
G0 through G3 are also used for In-System Emulation.
Port H is an 8-bit I/O port. All H pins have Schmitt triggers on
the inputs.
Port L is an 8-bit I/O port. All L-pins have Schmitt triggers on
the inputs.
Port L supports the Multi-Input Wake-up feature on all eight
pins. Port L has the following alternate pin functions:
L7 Multi-Input Wake-up
L6 Multi-Input Wake-up
L5 Multi-Input Wake-up or T2B (Timer T2B Input)
L4 Multi-input Wake-up or T2A (Timer T2A Input)
DOG enabled, otherwise it is a general purpose I/O
G7
G6
CLKDLY
Alternate SK
Config. Reg.
HALT
IDLE
Data Reg.
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