DS4830 Datasheet, PDF (26/29 Pages) Maxim Integrated Products – Optical Microcontroller 16-Bit MAXQ20 Low-Power Microcontroller

DS4830
Optical Microcontroller
DS4830
DEBUG
SERVICE
ROUTINES
(UTILITY ROM)
TMS
TAP
TCK
CONTROLLER
TDI
TDO
CPU
DEBUG
ENGINE
CONTROL
BREAKPOINT
ADDRESS
DATA
Figure 10. In-Circuit Debugger
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 10 shows a block diagram of the in-circuit debug-
ger. The in-circuit debug features include the following:
• A hardware debug engine
• A set of registers able to set breakpoints on register,
code, or data accesses (ICDA, ICDB, ICDC, ICDD,
ICDF, ICDT0, and ICDT1)
• A set of debug service routines stored in the utility ROM
The embedded hardware debug engine is an independ-
ent 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 fea-
tures 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 contin-
ues 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 reg-
isters and memory, and single-step trace operation.
Applications Information
Power-Supply Decoupling
To achieve the best results when using the DS4830,
decouple the V_DD power supply with a 0.1FF capaci-
tor. Use a high-quality, ceramic, surface-mount capaci-
tor if possible. Surface-mount components minimize
lead inductance, which improves performance, and
ceramic capacitors tend to have adequate high-frequen-
cy response for decoupling applications.Decouple the
REG285 and REG18 pins using 1FF and 10nF capacitors
(one each/per output). Note: Do not use either of these
pins for external circuitry.
Additional Documentation
Designers must have four documents to fully use all
the features of this device. This data sheet contains pin
descriptions, feature overviews, and electrical specifica-
tions. Errata sheets contain deviations from published
specifications. User guides offer detailed information
about device features and operation. The following docu-
ments can be downloaded from www.maxim-ic.com.
• This DS4830 data sheet, which contains electrical/
timing specifications, package information, and pin
descriptions.
• The DS4830 revision-specific errata sheet, if applicable.
• The DS4830 User’s Guide, which contains detailed
information and programming guidelines for core fea-
tures and peripherals.
Development and
Technical Support
Maxim and third-party suppliers provide a variety 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.maxim-ic.com/MAXQ_tools.
Email [e-mail] for techni-
cal support.
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