RCVDL56DPFL/SP, RCV56DPFL/SP, and RCV336DPFL/SP Designer’s Guide
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4.2 HOST DSP READ AND WRITE PROCEDURES
DSP RAM Write Procedure
1. Set MEMW to inform the DSP that a RAM write will occur when MEACC is set.
2. Load the RAM address into the MEADDH and MEADDL registers.
3. Write the desired data into the interface memory RAM data registers MEDAM and/or MEDAL.
4. Set MEACC to signal the DSP to perform the RAM write.
5. When the DSP has transferred the contents of the interface memory RAM data registers into RAM, the MDP resets the
MEACC bit and sets the NEWS bit to indicate DSP RAM write completion. If the NSIE bit is a 1, IRQ is asserted and
NSIA is set to inform the host that setting of the NEWS bit is the source of the interrupt request.
6. Upon the completion of IRQ servicing, write a 0 into the NEWS bit to clear the NSIA bit and to negate IRQ if no other
interrupt requests are pending.
DSP RAM Read Procedure
1. Reset MEMW to inform the DSP that a RAM read will occur when MEACC is set.
2. Load the RAM address code into the MEADDH and MEADDL registers.
3. Set MEACC to signal the DSP to perform the RAM read.
4. When the DSP has transferred the contents of RAM into the interface memory RAM data registers MEDAM and/or
MEDAL, the MDP resets the MEACC bit and sets the NEWS bit to indicate DSP RAM read completion. If the NSIE bit is
a 1, IRQ is asserted and NSIA is set to inform the host that setting of the NEWS bit is the source of the interrupt
request.
5. Upon the completion of IRQ servicing, write a 0 into the NEWS bit to clear the NSIA bit and to negate IRQ if no other
interrupt requests are pending.
4.3 RAM READ AND WRITE EXAMPLES
Figure 4-1 shows a flowchart of a procedure to change the DTMF tone duration using method 1.
Figure 4-2 shows a flowchart of a procedure to change the RTS-CTS delay using method 2.
Figure 4-3 shows a flowchart of a procedure to change the THRESHU value for TONEA using method 3.
Figure 4-4 shows a flowchart of a procedure to read EQM using method 4.
4.4 CHANGES TO RAM ADDRESSES
Some previously defined RAM locations were changed to optimize internal RAM usage. The addresses affected are those
above CXX (all are 16-bit access):
Old Address (Hex)
New Address (Hex)
CXX
48XX (bit 1Dh:6 is set as an extension to MEADDH)
E00-E1B
C80-C9B
E1C-E7F
C1C-C7F
E80-E9B
D80-D9B
E9C-EFF
D1C-D7F
F00-F1B
E80-E9B
F1C-F7F
E1C-E7F
F80-F9B
F80-F9B (no change)
F9C-FFF
F1C-F7F
Note: Old addresses in the range of CXX were often used in RCV288DPX and RCV336ACF workarounds. The old FXXh
and EXXh addresses were found under the voice AGC and DTMF detection parameters.
The method for reading and writing RAM remains unchanged.
Содержание RC336DPFL
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