Filter
Top Products
Adapter Host Registers
A-17
Register Definitions
A.2.2 Channel Parameter Register–CH_PARM @ Base_Address + 4 (Host)
This is used to pass parameter information for HOST_CMD register com-
mands as follows:
GO (Tx GO): Load CH_PARM with the address of the first transmit list be-
fore issuing the command. The list must be located on an 8-byte address
boundary (three LSBs must be 0).
GO (Rx GO): Load CH_PARM with the address of the first receive list be-
fore issuing the command. The list must be located on an 8-byte address
boundary (three LSBs must be 0).
Load CH_PARM and write the GO bit with no intervening DIO accesses, as the
DIO_DATA and CH_PARM registers share a common holding register. Driver
writers must ensure that the code that loads CH_PARM and writes the GO bit
is noninterruptable. Otherwise, an intervening DIO could occur, corrupting the
list address and resulting in unpredictable operation.
When read, the LSB of the CH_PARM register indicates the operating mode
of the PCI output buffers (5 V or 3 V) for diagnostic purposes. A value of 1 indi-
cates 5-V operation, a value 0 indicates 3-V operation.
In an adapter check, CH_PARM contains the cause of the adapter check (refer
to Adapter Check Interrupt. Int_type = 110b and Int_Vec 00h, subsection
4.4.8).