Maxim Integrated 16-2
MAX31782 User’s Guide
Revision 0; 8/11
SECTION 16: TEST ACCESS PORT (TAP)
The MAX31782 incorporates a test access port (TAP) and TAP controller for communication with a host device across
a 4-wire synchronous serial interface. The TAP can be used by the MAX31782 to support in-system programming and/
or in-circuit debug. The TAP is compatible with the JTAG IEEE standard 1149 and is formed by four interface signals
as described in Table 16-1. For detailed information on the TAP and TAP controller, refer to IEEE STD 1149.1 “IEEE
Standard Test Access Port and Boundary-Scan Architecture.”
Table 16-1. Test Access Port Pins
These pins default to the TAP/JTAG function on reset, which means that the part is always ready for in-circuit debugging
or in-circuit programming operations following any reset. Once an application has been loaded and starts running, the
TAP/JTAG port can still be used for in-circuit debugging operations. If in-circuit debugging functionality is not needed,
the associated port pins can be reclaimed for application use by setting the TAP bit (SC.7) bit to 0. This disables the
TAP/JTAG interface and allows the four pins to operate as normal port pins. See Figure 16-1.
Figure 16-1. TAP and TAP Controller
EXTERNAL PIN SIGNAL FUNCTION
TDO
(Test Data Output)
Serial-Data Output. This signal is used to serially transfer internal data to the external host. Data
is transferred least significant bit first. Data is driven out only on the falling edge of TCK, only dur-
ing TAP Shift-IR or Shift-DR states and is otherwise inactive.
TDI
(Test Data Input)
Serial-Data Input. This signal is used to receive data serially transferred by the host. Data is
received least significant bit first and is sampled on the rising edge of TCK. TDI is weakly pulled
high internally when TAP = 1.
TCK
(Test Clock Input)
Serial Shift Clock Provided by Host. When this signal is stopped at 0, storage elements in the
TAP logic must retain their data indefinitely. TCK is weakly pulled high internally when TAP = 1.
TMS
(Test Mode Select Input)
Mode Select Input. This signal is sampled at the rising edge of TCK and controls movement
between TAP states. TMS is weakly pulled high internally when TAP = 1.
TDO
TDI
WRITE
TCK
DEBUG
UPDATE-DR
UPDATE-DR
V
DD
TAP CONTROLLER
TMS
SYSTEM PROGRAM
READ
POWER-ON
RESET
BYPASS
INSTRUCTION REGISTER
7 6 5 4 3 2 1 0 s1 s0
2 1 0
2 1 0
V
DD
(26 páginas)
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Comentários a estes Manuais