IDT 89HPES64H16G2 User Manual page 6

IDT
Notes
PES64H16G2 User Manual
Type Abbreviation
Hardware Initialized HWINIT
Read Only and Clear
Read Clear and Write
Reserved Reserved
Read Only
Read and Write
Read and Write Clear RW1C
Read and Write when
Unlocked
Sticky
Switch Sticky SWSticky
Register bits are initialized by firmware or hardware mechanisms
such as pin strapping or serial EEPROM. (System firmware hard-
ware initialization is only allowed for system integrated devices.)
Bits are read-only after initialization and can only be reset (for
write-once by firmware) with reset.
RC Software can read the register/bits with this attribute. Reading the
value will automatically cause the register/bit to be reset to zero.
Writing to a RC location has no effect.
RCW Software can read the register/bits with this attribute. Reading the
value will automatically cause the register/bits to be reset to zero.
Writes cause the register/bits to be modified.
The value read from a reserved register/bit is undefined. Thus,
software must deal correctly with fields that are reserved. On
reads, software must use appropriate masks to extract the defined
bits and not rely on reserved bits being any particular value. On
writes, software must ensure that the values of reserved bit posi-
tions are preserved. That is, the values of reserved bit positions
must first be read, merged with the new values for other bit posi-
tions and then written back.
RO Software can only read registers/bits with this attribute. Contents
are hardwired to a constant value or are status bits that may be
set and cleared by hardware. Writing to a RO location has no
effect.
RW Software can both read and write bits with this attribute.
Software can read and write to registers/bits with this attribute.
However, writing a value of zero to a bit with this attribute has no
effect. A RW1C bit can only be set to a value of 1 by a hardware
event. To clear a RW1C bit (i.e., change its value to zero) a value
of one must be written to the location. An RW1C bit is never
cleared by hardware.
RWL Software can read the register/bits with this attribute. Writing to
register/bits with this attribute will only cause the value to be modi-
fied if the REGUNLOCK bit in the SWCTL register is set. When
the REGUNLOCK bit is cleared, writes are ignored and the regis-
ter/bits are effectively read-only.
Fields with this attribute are implicitly SWSticky (i.e., their value is
preserved across all resets, except switch fundamental reset).
Sticky Register/bits with this designation take on their initial value as a
result of a switch fundamental reset or partition fundamental reset.
Other resets have no effect.
Register/bits with this designation take on their initial value as a
result of a switch fundamental reset. Other resets have no effect.
Table 2 Register Terminology
4
Description
April 5, 2013