HD6417320 RENESAS [Renesas Technology Corp], HD6417320 Datasheet - Page 814

• Manufacturer Part Number: HD6417320
• Description: Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine Family / SH7700 Series
• Manufacturer: RENESAS [Renesas Technology Corp]

Section 22
22.4.3
Figure 22.7 shows the blocks diagram of DAA circuit. Ringing detect and dial pulse sending
sequence are described below.
(1)
After the first ringing interrupt occurs, counting starts with writing 1 into RCEN bit of CTR2.
AFE must be operating before counting, because periodic counter counts AFE_FS from falling
edge to next falling edge.
The value of RCNTV register is effective only after 2nd interrupt generation, because the value of
RCNTV register is transferred from counter with a trigger of ending of 1st period cycle.
RCNTV will be 258 H (600 in decimal) if ringing cycle is 16 Hz and counted by 9600 Hz which is
default value of AFE_FS. Figure 22.8 shows detecting sequence of ringing.
Rev. 3.00 Jan. 18, 2008 Page 752 of 1458
REJ09B0033-0300
Ringing Detect Sequence
AFEIF
DAA Interface
Analog Front End Interface (AFEIF)
AFE_RLYCNT
AFE_RDET
(STLC7550)
AFE
Figure 22.7
Hyblid circuit
DAA Block Diagram
DC holding
Ringing detector
circuit
Hook relay
Ring
Tip