4-38
Registers
also possible to program these signals as live inputs and
sense them through a SCRIPTS register to register Move
Instruction. GPIO[3:0] default as inputs and GPIO4
defaults as an output pin. When configured as inputs, an
internal pull-down is enabled.
LSI Logic software uses the GPIO[1:0] signals to access
serial EEPROM. GPIO1 is used as a clock, with the
GPIO0 pin serving as data.
LSI Logic software also reserves the use of GPIO[4:2]. If
there is a need to use GPIO[4:2], please check with
LSI Logic for additional information.
Register: 0x08
SCSI First Byte Received (SFBR)
Read/Write
This register contains the first byte received in any asynchronous
information transfer phase. For example, when a LSI53C896 SCSI
function is operating in the initiator mode, this register contains the first
byte received in the Message-In, Status, and Data-In phases.
When a Block Move instruction is executed for a particular phase, the
first byte received is stored in this register - even if the present phase is
the same as the last phase. The first byte received value for a particular
input phase is not valid until after a MOVE instruction is executed.
This register is also the accumulator for register read-modify-writes with
the
SCSI First Byte Received (SFBR)
as the destination. This allows bit
testing after an operation.
The
SCSI First Byte Received (SFBR)
is not writable using the CPU, and
therefore not by a Memory Move. However, it can be loaded using
SCRIPTS Read/Write operations. To load the SFBR with a byte stored
in system memory, the byte must first be moved to an intermediate
LSI53C896 SCSI function register (such as the SCRATCH register), and
then to the SFBR.
7
0
IB
0
0
0
0
0
0
0
0
*
Содержание LSI53C896
Страница 6: ...vi Preface...
Страница 16: ...xvi Contents...
Страница 88: ...2 62 Functional Description...
Страница 112: ...3 24 Signal Descriptions...
Страница 306: ...6 38 Specifications This page intentionally left blank...
Страница 310: ...6 42 Specifications This page intentionally left blank...
Страница 338: ...6 70 Specifications Figure 6 40 LSI53C896 329 BGA Bottom View...
Страница 340: ...6 72 Specifications...
Страница 346: ...A 6 Register Summary...
Страница 362: ...IX 12 Index...