z8f0813 ZiLOG Semiconductor, z8f0813 Datasheet - Page 162

• Manufacturer Part Number: z8f0813
• Description: High-performance 8-bit Microcontrollers
• Manufacturer: ZiLOG Semiconductor

Operation
PS024314-0308
Caution:
OCD Interface
Figure 23. Interfacing the On-Chip Debugger’s DBG Pin with an RS-232 Interface (1)
The following sections describes the operation of OCD.
The OCD 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, in that transmit and receive 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 from the Z8 Encore! XP F0823 Series products to
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
The recommended method is the buffered implementation depicted in
DBG pin has a internal pull-up resistor which is sufficient for some applications (for more
details on the pull-up current, see
operation at higher data rates or in noisy systems, an external pull-up resistor is
recommended.
RS-232 TX
RS-232 RX
For operation of the OCD, all power pins (V
and all ground pins (V
drain and may require an external pull-up resistor to ensure proper operation.
Transceiver
RS-232
SS
and AV
Electrical Characteristics
SS
) must be properly grounded. The DBG pin is open-
Schottky
Diode
DD
VDD
and AV
10 k
Z8 Encore! XP
DD
Ω
on page 193). For OCD
) must be supplied with power,
DBG Pin
Product Specification
Figure 23
Figure
®
On-Chip Debugger
F0823 Series
and
24. The
Figure
24.
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