Datasheet

In-Circuit Debug
Embedded debugging capability is available through the
JTAG-compatible test access port (TAP). Embedded
debug hardware and embedded ROM firmware provide
in-circuit debugging capability to the user application,
eliminating the need for an expensive in-circuit emulator.
Figure 12 shows a block diagram of the in-circuit debug-
ger. The in-circuit debug features include the following:
● Hardware debug engine
● Set of registers able to set breakpoints on register,
code, or data accesses (ICDA, ICDB, ICDC, ICDD,
ICDF, ICDT0, and ICDT1)
● Set of debug service routines stored in the utility ROM
The embedded hardware debug engine is an independent
hardware block in the microcontroller. The debug engine
can monitor internal activities and interact with selected
internal registers while the CPU is executing user code.
Collectively, the hardware and software features allow two
basic modes of in-circuit debugging:
● Background mode allows the host to configure and set
up the in-circuit debugger while the CPU continues to
execute the application software at full speed. Debug
mode can be invoked from background mode.
● Debug mode allows the debug engine to take control
of the CPU, providing read/write access to internal
registers and memory, and single-step trace operation.
Applications Information
Power-Supply Decoupling
To achieve the best results when using the DS4830A,
decouple the V
DD
power supply with a 0.1µF X5R
capacitor. Use a high-quality, ceramic, surface-mount
capacitor if possible. Surface-mount components mini-
mize lead inductance, which improves performance, and
ceramic capacitors tend to have adequate high-frequency
response for decoupling applications.
Decouple the REG274 and REG18 pins using 1µF X5R
and 10nF capacitors (one each/per output). Note: Do not
use either of these pins for external circuitry.
Additional Documentation
Designers must have three documents to fully use
all the features of this device. This data sheet con-
tains pin descriptions, feature overviews, and elec-
trical specifications. Errata sheets contain devia-
tions from published specifications. User guides offer
detailed information about device features and opera-
tion. The following documents can be downloaded from
www.maximintegrated.com/DS4830A.
● The DS4830A data sheet, which contains electrical/
timing specifications, package information, and pin
descriptions.
● The DS4830A revision-specific errata sheet, if appli-
cable.
● The DS4830A User’s Guide, which contains detailed
information and programming guidelines for core fea-
tures and peripherals.
Development and Technical Support
Maxim Integrated and third party suppliers provide a vari-
ety of highly versatile, affordably priced development tools
for this microcontroller, including the following:
● Compilers (C and assembly)
● In-circuit debugger
● Integrated development environments (IDEs)
● Serial-to-JTAG converters for programming and
debugging
● USB-to-JTAG converters for programming and
debugging
A partial list of development tool vendors can be found at
www.maximintegrated.com/MAXQ_tools.
Go to www.maximintegrated.com/support for addi-
tional technical support.
Figure 12. In-Circuit Debugger
DS4830A Optical Microcontroller
www.maximintegrated.com
Maxim Integrated │ 28
TAP
CONTROLLER
CPU
DEBUG
ENGINE
DEBUG
SERVICE
ROUTINES
(UTILITY ROM)
CONTROL
BREAKPOINT
ADDRESS
DATA
DS4830A
TMS
TCK
TDI
TDO