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STP2002QFP
Sun Microelectronics
Fast Ethernet, Parallel Port, SCSI (FEPS) - STP2002QFP
DSS:
Data setup to data strobe. This 7-bit quantity is used to define several differ-
ent timing specifications for the interface. The contents of this field of the reg-
ister are used to load a hardware timer whose timebase is the SBus clock. The
programmability range is from a minimum of 0 SBus clocks to 127 SBus
clocks. Bit 0 is the LSB and bit 6 is the MSB. The sections on unidirectional
and bidirectional transfers should be referenced for detail information on the
use of this timer.
DSW:
Data strobe width. This 7-bit quantity is used to define data strobe and ac-
knowledge pulse widths for the interface. The contents of this field of the reg-
ister are used to load a hardware timer whose timebase is the SBus clock. The
programmability range is from a minimum of 3 SBus clocks to 127 SBus
clocks. In the case of the value being 0, 1, 2, or 3, the timer will be loaded
with a value of 3. Bit 8 is the LSB and bit 14 is the MSB. The sections on uni-
directional and bidirectional transfers should be referenced for detail infor-
mation on the use of this timer.
7.2.6 Operation Configuration RegisterThis 16-bit read/write register is used to specify the operation of the interface.
Bidirectional specification of the control signals (P_D_STRB, P_ACK,
P_BSY), handshake protocol, memory clear, and diagnostic mode are defined
in this register. The detailed function of the bits is described in Table 30. Re-
set value of this register is all bits 0, exceptDS_DSELand IDLE, which are
reset to 1, and bit 1, which always reads as 1 for backward compatibility with
the HIOD parallel port.
Table 28: Hardware Configuration Register Definition
Field Bits Description Type
DSS 6:0 Data setup before data strobe in increments of 1 SBus clock R/W
7 Unused. Reads as 0 R
DSW 14:8 Data strobe width in increments of 1 SBus clock R/W
TEST 15 Test bit which when set, allows the buried counters to be
read
R/W