94
STP2002QFP
Sun Microelectronics
Fast Ethernet, Parallel Port, SCSI (FEPS) - STP2002QFP
When both bits read back as 0s, the software is allowed to continue to
program the hardware.
7.5.2 Global Configuration Register
This five-bit register is used to determine the system-related parameters that
control the operation of the DMA channels.
7.5.3 Global Interrupt Mask Register (RW)
This 32-bit register is used to determine which status events will cause an in-
terrupt. If a mask bit is cleared to 0, the corresponding event causes an inter-
rupt signal to be generated on the SBus. The layout of this register
corresponds bit-by-bit to the layout of the status register, with the exception
of bit [23]. The MIF interrupt is not maskable here, and should be masked at
the source of the interrupt in the MIF.
Default value is 0xFF7FFFFF.
Table 94: Global Configuration Register Address
Register Physical Address Access Size
Global configuration register 0x8C0_0004 4 bytes
Table 95: Global Configuration Register Definition
Field Bits Description Type
Burst_Size 1:0 This field determines the size of the host bus
bursts that the DMA channels will execute:
00 — 16-byte burst
01 — 32-byte burst
10 — 64-byte burst
11 — Reserved
R/W
Extended_Transfer_Mode 2 When set to 1, 64-bit CEI and SBus DVMA
transactions will be performed. If cleared to 0,
a 32-bit CEI/SBus is assumed
R/W
Parity_Enable 3 When set to 1, parity checking is performed
for DVMA read and PIO write cycles
R/W
27:4 Reserved R/W
Ethernet channel ID 31:28 This field identifies the version number of the
Ethernet channel. Current version # is 0000
R/W