
Advanced Notebook I/O for ISA or LPC Designs
Datasheet
Rev. 0.5 (03-24-05)
Page 248
SMSC SIO10N268
DATASHEET
Exit XNOR-Chain test mode as follows:
Devices configured for LPC Mode:
- On the rising (deasserting) edge of PCI_RESET#, drive either LFRAME# or LAD[0] high.
Devices configured for ISA Mode:
- On the falling (deasserting) edge of RESET_DRV, drive either nIORD or nIOWR high
The PCI_RESET#, nRESET_DRV, and LPC_ISA pins are not included in the XNOR-Chain. The XNOR-
Chain output pin# is 18, nIO_PME. See the following subsections for more details.
13.2
Pin List of XNOR Chain
Pins 1 to 128 on the chip are inputs to the first XNOR chain, with the exception of the following:
1) VCC (pins 25, 49, 70, 102, and 126) and VTR (pin 19).
2) VSS (pins 7, 27, 52, 74, and 109).
3) PCI_RESET# (pin 29), RESET_DRV (pin 59)
4) LPC_ISA (pin 54)
5) nIO_PME (pin 18) This is the chain output.
To put the chip in the first XNOR chain test mode:
LPC_Mode:
Tie LAD0 (pin 21) and LFRAME# (pin 26) low. Then toggle PCI_RESET# (pin 29) from a low to a
high state. Once the chip is put into XNOR chain test mode, LAD0 (pin 21) and LFRAME# (pin 26)
become part of the chain.
ISA_Mode:
Tie nIORD (pin 100) and nIOWR (pin 101) low. Then toggle RESET_DRV (pin 59) from a high to a
low state. Once the chip is put into XNOR chain test mode, nIORD (pin 100) and nIOWR (pin 101)
become part of the chain.
To exit the first XNOR chain test mode:
Devices configured for LPC Mode (default – LPC_ISA pin is unconnected or tied to ground):
- Tie LAD0 (pin 21) or LFRAME# (pin 26) high. Then toggle PCI_RESET# (pin 29) from a low to a
high state.
Devices configured for ISA Mode (LPC_ISA pin is tied to VCC):
- Tie nIORD (pin 100) or nIOWR (pin 101) high. Then toggle RESET_DRV (pin 59) from a high to a
low state.
NOTE:
A VCC POR will also cause the XNOR chain test mode to be exited, regardless of the Mode. To verify the
test mode has been exited, observe the output at nIO_PME (pin 18). Toggling any of the input pins in the
chain should not cause its state to change.
13.3
Setup of XNOR Chain
WARNING:
Ensure power supply is off during setup.
1) Connect VSS (pins 7, 27, 52, 74, and 109) to ground.
2) Connect VCC (pins 25, 49, 70, 102, and 126) and VTR (pin 19) to VCC (3.3V).