CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Telephone Function)

TCD0–TCD3: Telephone code for dialing (FF17H)

By writing code to this register, the dialer starts outputting the corresponding dial pulses (in pulse mode) or tone signals (in tone mode). When the output is finished, an interrupt occurs.

At initial reset, this register is set to "0000B".

The following shows the register settings for each mode.

(1)Pulse mode

In this mode, write data for a dial number (1–9, 0) to this register. Table 4.14.10.7 lists the relationship of writing codes and pulse counts.

Table 4.14.10.7 Relationship of code sand pulse counts

 

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.

(2)Tone mode

In this mode, write data for a push button (ROW, COL) to this register. Table 4.14.10.8 lists the relationship of writing codes and tone frequencies.

Table 4.14.10.8 Relationship of codes and tone frequencies

 

TCD code

 

Tone frequency

Key

D3

D2

D1

D0

symbol

0

 

0

0

 

0

(ROW1, COL4)

"A"

0

 

0

0

 

1

(ROW1, COL1)

"1"

0

 

0

1

 

0

(ROW1, COL2)

"2"

0

 

0

1

 

1

(ROW1, COL3)

"3"

0

 

1

0

 

0

(ROW2, COL1)

"4"

0

 

1

0

 

1

(ROW2, COL2)

"5"

0

 

1

1

 

0

(ROW2, COL3)

"6"

0

 

1

1

 

1

(ROW3, COL1)

"7"

 

TCD code

 

Tone frequency

Key

D3

D2

D1

D0

symbol

1

 

0

0

 

0

(ROW3, COL2)

"8"

1

 

0

0

 

1

(ROW3, COL3)

"9"

1

 

0

1

 

0

(ROW4, COL2)

"0"

1

 

0

1

 

1

(ROW4, COL3)

"#"

1

 

1

0

 

0

(ROW4, COL1)

"*"

1

 

1

0

 

1

(ROW2, COL4)

"B"

1

 

1

1

 

0

(ROW4, COL4)

"D"

1

 

1

1

 

1

(ROW3, COL4)

"C"

Writing data to this register triggers the start of the tone output. When single tone output is selected, either the ROW frequency or COL frequency corresponding to the written data is output as a tone signal. When dual tone output is selected, the specified ROW and COL frequencies are output after they are composed.

CRMUT: Receive mute control (FF18H•D1)

Controls the receive mute.

When "1" is written: Receive mute output

When "0" is written: Low level output on XRMUTE (R11) terminal

Reading: Valid

When "0" is written to the CRMUTE register, the XRMUTE (R11) terminal is pulled down to Low (VSS) level to mute the receive line.

When the CRMUTE register is set to "1", the XRMUTE (R11) terminal is controlled by the hardware and will be Low (VSS) level during a dialing pulse cycle or a flash cycle.

At initial reset, this register is set to "1".

S1C63558 TECHNICAL MANUAL

EPSON

133