ELANSC310 AMD [Advanced Micro Devices], ELANSC310 Datasheet - Page 37

• Manufacturer Part Number: ELANSC310
• Description: Single-Chip, 32-Bit, PC/AT Microcontroller
• Manufacturer: AMD [Advanced Micro Devices]

JTAG BOUNDARY SCAN INTERFACE
The ÉlanSC310 microcontroller provides an IEEE Std
1149.1-1990 (JTAG) compliant Standard Test Access
Port (TAP) and Boundary-Scan Architecture.
The boundary-scan test logic consists of a boundary
scan register and support logic that are accessed
through the TAP. The TAP provides a simple serial in-
terface that makes it possible to test the microcontroller
and system hardware in a production environment.
The TAP contains extensions that allow a hardware-
development system to control and observe the micro-
controller without interposing hardware between the
microcontroller and the system.
The TAP can be controlled via a bus master. The bus
master can be either automatic test equipment or a
component (PLD) that interfaces to the four-pin test
bus.
The JTAG pins described here are shared pin func-
tions. They are enabled by the JTAGEN signal.
JTAGEN
JTAG Enable (Input; Active High)
This pin enables the JTAG pin functions. When it is
High, the JTAG interface is enabled. When it is Low, the
JTAG pin functions are disabled and the pins are con-
figured to their default functions. See the Pin Designa-
tions, System Interface, and Miscellaneous Interface
tables for the JTAG pin default function descriptions.
For more information, see “System Test and Debug” on
page 64.
[TCK]
Test Clock (Input)
Test clock is a JTAG input clock that is used to access
the test access port when JTAGEN is active.
[TDI]
Test Data Input (Input)
Test data Input is the serial input stream for JTAG scan
input data when JTAGEN is active.
[TDO]
Test Data Output (3-State Output)
Test data Output is the serial output stream for JTAG
scan result data when JTAGEN is active.
[TMS]
Test Mode Select (Input)
Test Mode Select is an input for controlling the Test Ac-
cess Port when JTAGEN is active.
Élan™SC310 Microcontroller Data Sheet
P R E L I M I N A R Y
RESET AND POWER
See “Voltage Partitioning” on page 84 for more infor-
mation about power.
AGND
Analog Ground pin
This pin is the ground for the analog circuitry and is bro-
ken out separately from the other GND pins making it
possible to filter AGND in a system that has a lot of
noise on the ground plane. In most applications, AGND
is tied directly to the ground plane with the other ground
pins on the microcontroller.
AVCC
3.3 V (only) Supply Pin
This supply pin provides power to the analog section of
the ÉlanSC310 microcontroller’s internal PLLs. Ex-
treme care should be taken that this supply voltage is
isolated properly to provide a clean, noise-free voltage
to the PLLs.
AVCC is required for battery backup. For more informa-
tion about battery backup, see the Élan
Élan
Using a Back-Up Battery Application Note , order
#20746.
GND
System Ground Pins
These pins provide electric grounding to all non-analog
sections of the ÉlanSC310 microcontroller’s internal
CPU and peripherals.
IORESET
Reset Input (Input; Active Low)
IORESET is an asynchronous hardware reset input
equivalent to POWERGOOD in the PC/AT system ar-
chitecture. Asserting this signal does not reset the RTC
RAM invalid bit.
Asserting IORESET without asserting RESIN causes
the ÉlanSC310 microcontroller to enter Micro Power
Off mode. For more information, see “Micro Power Off
Mode” on page 46.
RESIN
Master Reset (Input; Active Low)
RESIN indicates that main power is initially being ap-
plied to the ÉlanSC310 microcontroller for the first time.
When this signal is asserted, the RTC and Internal reg-
isters are reset.
The RESIN signal supersedes the IORESET signal.
TM
SC310 Microcontrollers Solution For Systems
TM
SC300 and
37