tspc860 ATMEL Corporation, tspc860 Datasheet - Page 27

• Manufacturer Part Number: tspc860
• Description: Integrated Communication Processor
• Manufacturer: ATMEL Corporation

JTAG and Debug Ports
Unused Inputs
Unused Outputs
Signal States During
Hardware Reset
2129B–HIREL–12/04
MODCK[1-2] must be used to determine the default clocking mode for the TSPC860.
After hardware reset, the MODCK[1-2] pins change function and become outputs. Thus,
if these alternate functions are also desired, then the MODCK[1-2] configuration should
be set with three-state drivers that turn off after HRESET is negated; however, if
MODCK[1-2] pins’ alternate output functions are not used in the system, they can be
configured with pull-up and pull-down resistors.
Signals with open-drain buffers and active pull-up buffers (HRESET, SRESET, TEA, TS,
TA, BI, and BB) must have external pull-up resistors. These signals include the
following:
Some other input signals do not absolutely require a pull-up resistor, as they may be
actively driven by external logic. However, if they are not used externally, or if the exter-
nal logic connected to them is not always actively driving, they may need external pull-
up resistors to hold them negated. These signals include the following:
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TCK/DSCK or ALE_B/DSCK/AT1 (depending on the configuration of the DSCK func-
tion) should be connected to ground through a pull-down resistor to disable Debug
Mode as a default. When required, a debug mode controller tool externally drives this
signal high actively to put the TSPC860 into debug mode.
Two pins need special attention, depending on the version of TSPC860 used.
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To allow application of any version of processor, perform both of the above actions.
In general, pull-up resistors should be used on any unused inputs to keep them from
oscillating. For example, if PCMCIA is not used, the PCMCIA input pins (WAIT_A,
WAIT_B, IP_A[0-8], IP_B[0-8]) should have external pull-up resistors. However, unused
pins of port A, B, C, or D can be configured as outputs, and, if they are configured as
outputs they do not require external terminations.
Unused outputs can be left unterminated.
During hardware reset (HRESET or PORESET), the signals of the TSPC860 behave as
follows:
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PORESET
AS
CR/IRQ3
KR/RETRY/IRQ4/SPKROUT (if configured as KR/RETRY or IRQ4)
Any IRQx (if configured as IRQx)
BR (if the TSPC860’s internal bus arbiter is used)
BG (if an external bus arbiter is used)
For TSPC860 rev B and later, TDI/DSDI should be pulled up to V
oscillating when unused.
For TSPC860 rev A.3 and earlier, TCK/DSCK should be connected to ground if it is
configured for its DSCK function, as stated above. However, for these versions of
the TSPC860, the pull-down resistor must be strong (for example, 1 k to overcome
the internal pull-up resistor.
The bus signals are high-impedance
The port I/O signals are configured as inputs, and are therefore high-impedance
The memory controller signals are driven to their inactive state
CC
to keep it from
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