COP8SA-DM National Semiconductor, COP8SA-DM Datasheet - Page 70

• Manufacturer Part Number: COP8SA-DM
• Description: MODULE DEBUGGING FOR COP8SA
• Manufacturer: National Semiconductor

Specifications of COP8SA-DM

• Module/board Type: Debugger Module
• For Use With/related Products: Cop 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *COP8SA-DM

MIMW typically reduces current consumption down to less than 4 A during quiescent states —
compared to 6 A of current consumption if code remained running. In addition, MIWU
makes hardware design easier and more efficient by reducing component count,
obviating the need for glue logic.
In a laptop keyboard application, for example, the L port is used as the keyboard input
lines.
The microcontroller is in the HALT mode until a keystroke or data transmission -to-low
transition on one of the lines, compelling the device to exit the HALT mode. The keyboard
is than scanned to detect which key is pressed, and the appropriate key-code is sent to
the computer. When the scan is complete, the microcontroller is switched back to the
HALT mode (Figure 2-21).
With features such as Multi-Input Wake-up, HALT and IDLE, and low voltage and
current drain capabilities, National’s COP8SAx7 family of 8-bit microcontrollers is doing
its part to reduce power consumption. And with “current” trends pointing to an
environment where less is indeed more, that’s putting real power back in the hands of
today’s embedded control system design.
The Multi-Input Wakeup feature utilizes the L Port. The user selects which particular L
port bit (or combination of L Port bits) will cause the device to exit the HALT or IDLE
modes. The selection is done through the register WKEN. The register WKEN is an 8-bit
read/write register, which contains a control bit for every L port bit. Setting a particular
WKEN bit enables a Wakeup from the associated L port pin.
2-32
COP8SAx7 MICROCONTROLLER
CONTINUOUS SCANNING
SCAN KEYBOARD
KEY ENCODING
KEY DECODING
CHANGE?
OUTPUT
START
Figure 2-21 Keyboard Scanning
LOWEST POWER CONSUMPTION
MIWU, EVENT-DRIVEN
EXTERNAL EVENT
SCAN KEYBOARD
KEY DECODING
KEY ENCODING
OUTPUT
START
MIWU
HALT