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CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Telephone Function)
The inter-digit pause time is the interval between digits of a dial number. It can be selected from among
15 types within 94 msec to 1,406 msec using the IDP3–IDP0 register (FF15H) as shown in Table 4.14.5.1.
D3
0
0
0
0
0
0
0
0
Do not write "0" (0000B) to the IDP register because it may cause a malfunction.
At initial reset, the inter-digit pause time is set to 750 msec (IDP = "1000B").
The following summarizes initial setting items that must be set before outputting dial pulses:
1. Set to pulse mode (TPS = "1").
2. Select a pulse rate (10 pps or 20 pps) using DRS.
3. Select a make ratio (40:60 or 33.3:66.6) using MB.
4. Select an inter-digit pause time (94 msec to 1,406 msec) using IDP.
The following explains how to output dial pulses and the circuit operation.
First, write "1" to the HSON register (FF18H•D3) so the dialer is in off-hook status. As a result, the DP
terminal goes High (V
DD
Next, write a digit of the dial number to be transmitted to the TCD3–TCD0 register (FF17H). Table
4.14.5.2 shows the relationship of write data and pulse counts.
D3
0
0
0
0
0
0
0
0
Do not write "0" (0000B) to the TCD register because it may cause a malfunction.
For a dial number between "1" to "9", the number is used for the pulse count as is. Dial number "0"
represents 10 pulses, so write "10" (1010B) to the TCD register.
Writing data to the TCD register triggers the start of the pulse output.
Figure 4.14.5.2 shows a pulse output timing chart.
120
Table 4.14.5.1 Selection of inter-digit pause time
IDP
Inter-digit pause
D2
D1
D0
time (msec)
0
0
0
Unavailable *
0
0
1
94
0
1
0
188
0
1
1
281
1
0
0
375
1
0
1
469
1
1
0
563
1
1
1
656
) level.
Table 4.14.5.2 Pulse count selection
TCD code
Pulse count
D2
D1
D0
0
0
0
Unavailable *
0
0
1
1
0
1
0
2
0
1
1
3
1
0
0
4
1
0
1
5
1
1
0
6
1
1
1
7
IDP
Inter-digit pause
D3
D2
D1
D0
time (msec)
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
TCD code
Pulse count
D3
D2
D1
D0
1
0
0
0
1
0
0
1
1
0
1
0
1
0
1
1
1
1
0
0
1
1
0
1
1
1
1
0
1
1
1
1
EPSON
750
844
938
1031
1125
1219
1313
1406
8
9
10
11
12
13
14
15
S1C63558 TECHNICAL MANUAL
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