Data Sheet
PowerPC 970FX
Preliminary
Table 5-8. Input/Output Signal Descriptions (Continued)
Pin Name
Width
In/Out
In
System/Debug Function
Notes
—
SRESET
1
2
2
2
2
1
System: Soft reset
SRIN(0:1)
In
System: EI Snoop response in
—
SRIN(0:1)
In
System: EI Inverse of Snoop response in
System: EI Snoop Response out
System:EI Inverse of Snoop Response out
Manufacturing test use only
—
SROUT(0:1)
SROUT(0:1)
SYNC_ENABLE
Out
Out
In
—
—
4
SYSCLK
SYSCLK
2
1
1
1
1
In
In
System Reference clock (differential input)
—
—
TBEN
TCK
TDI
System: Time base enable
JTAG: Test Clock which is separate from system clock. Controls all Test
Access Port functions
In
2
2
In
JTAG: Serial input used to feed test data and Test Access Port instructions.
JTAG: Serial output used to extract data from the chip under test control.
TDO
Out
—
THERM_INT
TMS
1
1
1
In
In
In
System: External thermal interrupt when low
—
—
—
JTAG: Select used to control the operation of the JTAG state machine
Initiate trace collection from outside
TRIGGERIN
Signal to indicate internal trace collection has begun.
TRIGGEROUT
1
1
Out
In
—
2
TRST
JTAG: Asynchronous Reset for the JTAG state machine.
Notes:
1. These are test signals for factory use only and must be pulled up to OVDD for normal processor operation.
2
2. For I C or JTAG operation, must be pull down with a 10K resistor to GND. Refer to Section 3.10.3.
3. Bus ratios 8:1 and 16:1 are not supported for Elastic Input (EI) functionality.
4. These are test signals for factory use only and must be pulled down to GND for normal processor operation.
5. This signal should not be connected.
6. These pins may be used to measure on-chip voltage drop and noise. They should be connected to a backside probe point
immediately behind the module. They should not be connected to GND and V planes.
DD
7. BiDi = Bidirectional.
8. Using the 4:1 or 12:1 ratio with multiplier of 12 will limit the use of the PowerTune to (freq)/2.
9. The PLL_MULT and PLL_RANGE(1:0) bits may be overwritten by JTAG commands and the BUS_CFG bits may be changed by
SCOM commands during the POR (power on reset) sequence. Refer to the POR Application Note for more details
10. Must be pull down with a 10K resistor to GND
System Design Information
October 14, 2005
Page 68 of 74
IBM [ IBM ]
