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.

Table 4.14.5.1 Selection of inter-digit pause time

 

IDP

 

Inter-digit pause

D3

D2

D1

D0

time (msec)

0

0

0

0

Unavailable *

0

0

0

1

94

0

0

1

0

188

0

0

1

1

281

0

1

0

0

375

0

1

0

1

469

0

1

1

0

563

0

1

1

1

656

 

IDP

 

Inter-digit pause

D3

D2

D1

D0

time (msec)

1

0

0

0

750

1

0

0

1

844

1

0

1

0

938

1

0

1

1

1031

1

1

0

0

1125

1

1

0

1

1219

1

1

1

0

1313

1

1

1

1

1406

∗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 (VDD) level.

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.

Table 4.14.5.2 Pulse count selection

 

TCD code

 

Pulse count

D3

D2

D1

D0

 

0

 

0

0

 

0

Unavailable *

0

 

0

0

 

1

1

0

 

0

1

 

0

2

0

 

0

1

 

1

3

0

 

1

0

 

0

4

0

 

1

0

 

1

5

0

 

1

1

 

0

6

0

 

1

1

 

1

7

 

TCD code

 

Pulse count

D3

D2

D1

D0

 

1

 

0

0

 

0

8

1

 

0

0

 

1

9

1

 

0

1

 

0

10

1

 

0

1

 

1

11

1

 

1

0

 

0

12

1

 

1

0

 

1

13

1

 

1

1

 

0

14

1

 

1

1

 

1

15

∗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

EPSON

S1C63558 TECHNICAL MANUAL