Table 5-6. Input/Output Use (Sheet 2 of 4)
750FL Micropro-
Input/
Input/Output with
Internal
Pullup Resistors
Required
External
Resistor
cessor Signal
Name
Active Level
Usage Group
Level Protect
Comments
Notes
Output
DH[0:31]
High
High
High
Low
Low
Input/Output
Input/Output
Input/Output
Input
Data Bus
Data Bus
Keeper
Keeper
1, 3, 4
1, 3, 4
DL[0:31]
DP[0:7]
DRTRY
GBL
Keeper
Keeper
3, 4
Input/Output
Transfer Attributes
Power Supply
Interrupt/Resets
Interrupt/Resets
LSSD
1, 3, 4
GND
HRESET
INT
Low
Low
High
High
Low
Low
Input
Input
Input
Input
Input
Input
Keeper
Keeper
Active driver
2, 3, 4, 5
Active driver or pullup
3, 4, 5
L1_TSTCLK
L2_TSTCLK
LSSD_MODE
MCP
Not enabled
Not enabled
Not enabled
5k Ω
5k Ω
5k Ω
Pullup/pulldown, as required
Pullup required to OVDD
Pullup required to OVDD
Active driver or pullup
5
LSSD
5
5
LSSD
Interrupt/Resets
Power Supply
Clock Control
Keeper
3, 4, 5
OVDD
PLL_CFG[0:4]
PLL_RNG[0:1]
QACK
High
High
Low
Low
Low
Low
Low
Input
Input
Keeper
Keeper
Keeper
Keeper
Keeper
Keeper
Keeper
As required Pullup/pulldown, as required
As required Pullup/pulldown, as required
Must be actively driven
3, 4, 5
3, 4, 5
3, 4, 5
3, 4, 5
3, 4, 5
3, 4
Input
Control
QREQ
Output
Output
Input
Status/Control
Chip actively drives
RSRV
No connect
SMI
SRESET
Notes:
Input
Interrupt/Resets
Active driver or pullup
2, 3, 4, 5
1. Depends on the system design. The electrical characteristics of the 750FL microprocessor do not add additional constraints to the system design. Therefore, whatever is
done with the net depends on the system requirements.
2. HRESET, SRESET, and TRST are signals used for ESP and RISCWatch to enable the correct operation of the debuggers. Logical AND gates must be placed between
these signals and 750FL microprocessor. (See Figure 5-7 IBM RISCWatch JTAG to HRESET, TRST, and SRESET Signal Connector on page 55.)
3. The 750FL microprocessor provides protection from metastability on inputs through the use of a “keeper” circuit on specific inputs. See Section 5.5 Level Protection on
page 55 for a more detailed description.
4. If a system design requires a signal level to be maintained while not being actively driven, an external resistor or device must be used (keepers assure no metastability of
inputs but do not guarantee a level).
5. The 750FL microprocessor does not require external pullups on address and data lines. Control lines must be treated individually.
IBM [ IBM ]
