AVG EZTouch I/O Jr., Manual

Page: 39 / 52

EZTouch I/O
Jr.
39 / 52
Register Internals (Word)
Internal Registers are denoted using an “R” pre-fix (e.g. R1, R4, etc.). These are
16-bit Word data types (registers). There are 8192 Internal Registers available in
the
EZTouch I/O
Jr. R are Read-Write type of data registers.
System
System Discretes (Discrete)
System Discretes are denoted using an “SD” prefix (e.g. SD1, SD4, etc.). SDs are
discrete memory locations with pre-assigned functionality. There are many
different types of System Discretes. They are used to help in logic program
development, provide system operating status info and more.
Note: Only SD1- 4 is used by the
EZTouch I/O
Jr. while programming.
System Registers (Word)
System Registers are denoted using an “SR” prefix (e.g. SR1, SR4, etc.). These are
16-bit Word data types (registers). System registers are Read-Write type data
points.
Note: Although, there are 20 System Registers available in the programming
software, only SR 1-9 are used by the
EZTouch I/O
Jr.
Index and Value Registers (Word)
The Index Register data type is represented by an “XR” prefix (e.g. XR1, XR2 etc.).
There are 4 XR memory locations available in
EZTouch I/O
Jr. “XR” is a Read-
Write data type and it is mainly used to point to the correct address of “R”
registers. The pointed-to “R” registers data value is stored in “#R” registers.
Value Register data type is represented by a “#R” prefix (e.g. #R1, #R2 etc.).
There are 4 #R memory locations available in
EZTouch I/O
Jr. “#R” is a Read-
Write data type and it is mainly used to read/write value of “R” registers as
pointed out by “XR” registers.
Both XR and #R registers are used in conjunction with each other and provide a
convenient way of addressing R registers.
Example:
Let's assume data values: R59=9874, R8000=32
If XR1=59
Then #R1=9874 (the actual data value of R59)
If XR2=8000
Then #R2=32 (the actual data value of R8000)
XR contains the address of the operand (or specifies a register that contains the
effective address), #R is used to read or write the actual operand. Indirect
addressing is often combined with pre- or post-increment (or decrement)
addressing. This allows the address of the operand to be increased or decreased
by the specified number either before or after using it. Proper usage of XR
variables often saves a lot of programming.