Motorola DSP96002 - Manual (Page 126)

7 - 40 DSP96002 USER’S MANUAL MOTOROLA
5. In the DSP96002 side, the X/Y/P Memory Write interrupt vector should point to a routine that
first reads HRX to get the address A, stores A in an address pointer Rn, and then again reads
HRX to retrieve the data D and store D into the DSP96002 memory location pointed by Rn.
6. The host processor may test TRDY to see if both A and D were removed from the input double
buffer (TX/HRX).
Figure 7-22 shows a flowchart for X Memory Write.
The following code is executed by the master processor. The R3 register contains the address needed for
selecting the "TX register write and X Memory Write interrupt" host function in the slave HI, as defined in
Figure 7-12. The R4 register contains the address needed for reading the ICS register of the slave HI. The
R1 register contains the target X memory address. The R0 register contains the data to be written to the
target X memory address. The master executes the following instructions:
DSP 96002 MASTER PROCESSOR DSP 96002 SLAVE PROCESSOR
Semaphore Control Semaphore Register (SEM)
1.Set Semaphore in slave’s
Semaphore Register using
BSET Instruction.
2.If Semaphore was set before
repeat step 1 else continue
X Memory Write Interrupt/Status Register
1.Check if the slave’s TX
register is empty (TXDE=1)
2.If TXDE=0
repeat step 1 else continue
3.Write the X memory address
to the slave’s "TX register
+ X Memory Write Interrupt"
(
—
H
–
S=0,
—
H
–
A=1, A5-A2=0010)
4.Check if the slave’s TX
register is empty (TXDE=1)
5.If TXDE=0
repeat step 4 else continue
6.Write the data
to the slave’s TX register
+ X Memory Write Interrupt
(
—
H
–
S=0,
—
H
–
A=1, A5-A2=0010) X Memory Write Interrupt Pend
Start Interrupt Processing
1.Move contents of Host HRX
Register to AGU Register:
When was interrupt serviced? MOVEP X:HRX,Rn
2.Move contents of Host HRX
If both address and data are Register to X Memory Addr:
read from HRX, TRDY = 1. MOVEP X:HRX,X:(Rn)
Figure 7-22. X Memory Write Procedure