Table of Contents
Advertisement
CHAPTER 15 MULTIPLICATION AND ADDITION CALCULATOR
[bit6, bit5, bit4] USR2, USR1, USR0 (Set a jump condition.): Read/Write
• This bit is referred by the multiplication and addition macro conditional branching command (when
COND bit =1). A jump is performed if the value of this bit matches the conditional branching command
UBP flag (condition attained). In other words, it is possible to switch between 8 different calculation
routines from the CPU by combining this conditional branching command with the calculation
commands.
• At reset: Be initialized to "000
• The read / write is possible.
[bit3] IrqDSP (interrupt request flag): Read/Write
• This flag indicates that the multiplication and addition macro has generated a software interrupt request.
When interrupt requests are enabled (IeDSP = 1), setting this bit creates an interrupt request for the
CPU.
• Multiplication and addition macro interrupt requests are generated by the software, by setting the STR
or JMP command SIRQ bit to "1".
Set factor: Set via the generation of a multiplication and addition macro software interrupt (STR/JMP
Clear factor : Clear by writing "0" [initial value]
• At reset: Be initialized to "0". (no interrupt request)
• The read / write is possible. Note, however, that only "0" can be written. Writing "1" will not change the
bit value.
• For read-modify-write commands, the value of "1" is always read, regardless of the value of the bit.
[bit2] leDSP (interrupt request enable bit): Read/Write
Interrupt requests to the CPU (IrqDSP = 1) are controlled as follows.
0: Interrupt request output disabled (setting IrqDSP will not generate an interrupt) [initial value]
1: Interrupt request output enabled (setting IrqDSP will generate an interrupt)
• At reset: Be initialized to "0". (interrupt request output is disabled.)
• The read / write is possible.
[bit1] HltDSP (calculation stop): Write only
• This bit forcibly stops calculation.
• When "1" is written to this bit, if calculation is being performed (RunDSP = 1), calculation will halt
after the currently executing command terminates (if it is a two-cycle command, after two cycles), and
the RunDSP flag is cleared.
• If calculation is stopping, this has not effect.
• If a stop is forced via this bit, DSP-PC points to the command address following the stopped command.
It is thus possible to continue with command execution.
- Forcibly stop by writing "1".
- Writing "0" is invalid. "0" is always read.
• At reset: Be initialized to "0".
356
".
B
command).
Advertisement
Table of Contents
