DM-COP8/20D National Semiconductor, DM-COP8/20D Datasheet - Page 85

• Manufacturer Part Number: DM-COP8/20D
• Description: CABLE FOR DEBUG MODULE 20-DIP
• Manufacturer: National Semiconductor

Specifications of DM-COP8/20D

• Accessory Type: 20-DIP Target Cable
• For Use With/related Products: MetaLink Debug Module
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *DM-COP8/20D

is read as all 1's, which in turn will cause the program to return to address 7FFF Hex.
This is an undefined ROM location and the instruction fetched (all 0's) from this location
will generate a software interrupt signaling an illegal condition.
Thus, the chip can detect the following illegal conditions:
When the software interrupt occurs, the user can re-initialize the stack pointer and do a
recovery procedure before restarting (this recovery program is probably similar to that
following reset, but might not contain the same program initialization procedures). The
recovery program should reset the software interrupt pending bit using the RPND
instruction.
2.15 MICROWIRE/PLUS
MICROWIRE/PLUS is a serial SPI compatible synchronous communications interface.
The MICROWIRE/PLUS capability enables the device to interface with MICROWIRE/
PLUS or SPI peripherals (i.e. A/D converters, display drivers, EEPROMs etc.) and with
other microcontrollers which support the MICROWIRE/PLUS or SPI interface. It
consists of an 8-bit serial shift register (SIO) with serial data input (SI), serial data
output (SO) and serial shift clock (SK). Figure 2-25 shows a block diagram of the
MICROWIRE/PLUS logic.
The shift clock can be selected from either an internal source or an external source.
Operating the MICROWIRE/PLUS arrangement with the internal clock source is called
the Master mode of operation. Similarly, operating the MICROWIRE/PLUS
arrangement with an external shift clock is called the Slave mode of operation.
LINES
I/O
1. Executing from undefined ROM
2. Over “POP”ing the stack by having more returns than calls.
(MASTER)
COP8
SI
SO
SK
Figure 2-25 MICROWIRE/PLUS Application
5
D0
A/D CON-
VERTER
8-BIT
SK
DI
D0
EEPROM
CHIP SELECT LINES
SK
DI
DISPLAY
DRIVER
LCD
SK
COP8SAx7 MICROCONTROLLER
DI
DISPLAY
DRIVER
VF/LED
SK
DI
SO
SI
SK
(SLAVE)
COP8
LINES
I/O
2-47