z8f083a ZiLOG Semiconductor, z8f083a Datasheet - Page 146

• Manufacturer Part Number: z8f083a
• Description: High-performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

Operation
PS026308-1207
OCD Interface
Caution:
Figure 18. Interfacing the On-Chip Debugger’s DBG Pin with an RS-232 Interface (1)
The On-Chip Debugger uses the DBG pin for communication with an external host. This
one-pin interface is a bidirectional open-drain interface that transmits and receives data.
Data transmission is half-duplex, which means transmission and data retrieval cannot
occur simultaneously. The serial data on the DBG pin is sent using the standard
asynchronous data format defined in RS-232.This pin creates an interface between the Z8
Encore! F083A Series products and the serial port of a host PC using minimal external
hardware.Two different methods for connecting the DBG pin to an RS-232 interface are
displayed in
buffered implementation depicted in
connected to V
RS-232 TX
RS-232 RX
For operation of the On-Chip Debugger, all power pins (V
must be supplied with power, and all ground pins (V
properly grounded.
The
an external pull-up resistor to insure proper operation.
DBG
Figure 18
DD
pin is open-drain and must always be connected to V
through an external pull-up resistor.
Transceiver
and
RS-232
Figure 19
Figure 19
on page 135. The recommended method is the
Schottky
Diode
on page 135. The DBG pin must always be
VDD
10KOhm
Z8 Encore!
SS
DBG Pin
and AV
Product Specification
DD
DD
SS
and AV
®
) must be
On-Chip Debugger
through
F083A Series
DD
)
134