AT89LP216 Atmel Corporation, AT89LP216 Datasheet - Page 63

• Manufacturer Part Number: AT89LP216
• Manufacturer: Atmel Corporation

Specifications of AT89LP216

• Flash (kbytes): 2 Kbytes
• Max. Operating Frequency: 20 MHz
• Cpu: 8051-1C
• Max I/o Pins: 14
• Spi: 1
• Uart: 1
• Sram (kbytes): 0.125
• Operating Voltage (vcc): 2.4 to 5.5
• Timers: 2
• Isp: SPI/OCD
• Watchdog: Yes

23. On-chip Debug System
23.1
3621E–MICRO–11/10
Physical Interface
The AT89LP216 On-chip Debug (OCD) System uses a two-wire serial interface to control pro-
gram flow; read, modify, and write the system state; and program the nonvolatile memory. The
OCD System has the following features:
The On-chip Debug System uses a two-wire synchronous serial interface to establish communi-
cation between the target device and the controlling emulator system. The OCD interface is
controlled by two User Fuses. OCD is enabled by clearing the OCD Enable Fuse. When OCD is
enabled, the RST port pin is configured as an input for the Debug Clock (DCL). Either the XTAL1
or XTAL2 pin is configured as a bi-directional data line for the Debug Data (DDA) depending on
the clock source selected. If the External Clock is selected, XTAL2 is configured as DDA. If the
Internal RC Oscillator is selected, XTAL1 is configured as DDA. The OCD device connections
are shown in
two-wire interface (FTWI). It is the duty of the user to program these fuses to the correct settings
before using the device in their debug system (see
Figure 23-1. AT89LP216 On-chip Debug Connections
When designing a system where On-chip Debug will be used, the following observations must
be considered for correct operation:
• Complete program flow control
• Read-modify-write access to all internal SFRs and data memories
• Four hardware program address breakpoints
• Unlimited program software breakpoints using BREAK instruction
• Break on stack overflow/underflow
• Break on Watchdog overflow
• Non-intrusive operation
• Programming of nonvolatile memory
• P1.3/RST cannot be connected directly to V
• All external reset sources must be removed.
• The quartz crystal and any capacitors on XTAL1 or XTAL2 must be removed and an external
must be removed.
clock signal must be driven on XTAL1 if the user does not wish to use the internal RC
oscillator. Some emulator systems may provide a user-configurable clock for this purpose.
DDA
DCL
Figure
23-1. The OCD Interface Select User Fuse should always be set for the fast
P1.3/RST
XTAL1
GND
CLK = Internal RC
VCC
CC
DCL
CLK
and any external capacitors connect to RST
“User Configuration Fuses” on page
CLK = External Clock
P1.3/RST
XTAL1
GND
XTAL2
VCC
AT89LP216
DDA
71).
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