BU8307CS datasheet(12/17 Pages) ROHM

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174

Communication ICs

BU8307CS / BU8307CF

FPin descriptions

(1)

ROW1 to ROW4 and COL1 to COL4

These are the keyboard input pins. They can be con-

nected to a 3

4 (2 of 7) standard keypad, or a 4

keypad. Key input becomes valid by either shorting a

single ROW input and a single COL input, or setting a

single ROW and a COL input to LOW at the same time.

If two keys are pressed at the same time, the key input

is ignored. In tone mode, a single tone can be generated

by pressing two or more keys in the same row or column

of the ROW1 to ROW4 and CL1 to COL3 matrices. If the

two keys are not in the same row or column, the key input

will be ignored.

(2)

This is the hook switching input pin. When this pin is

LOW, the state is perceived as off-hook, and when HIGH

, as on-hook. The pin is set to the off-hook state during

a dial signal transmission, and to the on-hook state dur-

ing memory hold.

(3)

67% / 60%

This switches the dial pulse break ratio. In LOW state, the

ratio is 60%, and in HIGH state, 67%.

(4)

MODEOUT

This is the output pin for the mode state. When the output

mode is set to the pulse mode, this pin is Z level, and

when the output mode is set to the tone mode, this pin is

LOW. It goes to Z level when on-hook. The output is Nch

open drain output.

(5)

MODEIN

This is the input pin for the mode state. When LOW, the

tone mode is effective, and when Z, the pulse mode at

10pps is effective, and when HIGH, the pulse mode at

20pps is effective.

If the T key is input, however, the mode switches to the

tone mode, even if this pin is HIGH or Z state.

If this pin is set to HIGH or LOW level by applying resis-

tance, the resistance level should be 10k

Ω or less.

(6)

OSCIN and OSCOUT

These are the input and output pins for the internal oscilla-

tor. A crystal resonator or ceramic resonator

(CSA3.58MGU300AB or CST3.58MGWU300AB) is con-

nected between OSCIN and OSCOUT. If CSA3.58

MGU300AB is connected, a CH-type 30 pF capacitor

should be connected between each of these pins and VSS.

(7)

KEYTONE

This is the pin which outputs keytones. It has a CMOS

output. When off-hook, this pin outputs a key-press con-

firmation tone for all valid key input in pulse mode, and

for valid input of the PA , R , and H keys in tone mode.

The output frequency fKT is 1193Hz and the output time

tKT is 34ms. When there is no output, this pin is LOW.

(8)

LH / SH

This pin switches the hooking time. When LOW, the

hooking time is 84ms, and when HGH, 607 ms.

(9)

DTMF

In tone mode, this pin outputs the corresponding DTMF

signal when a key is pressed. It is LOW level except when

a DTMF signal is being sent. This has CMOS output. A

20k

Ω resistor should be connected between this pin and

VSS.

(10) MFMUTE

This goes LOW when a DTMF signal is sent. When there

is no output, and when on-hook, it goes to Z level. This

is Nch open drain output.

(11) DPMUTE

When a dial pulse is being sent, and when an on-hook se-

quence is in progress, this goes LOW. In tone mode,

when there is no output, and in on-hook state, this goes

to Z level. The output is Nch open drain output.

(12) DP

In pulse mode, this pin outputs the corresponding dial

pulse when a key is pressed. It goes to Z level for a con-

tact make and to LOW level for a contact break. It re-

mains at Z level unless a dial pulse is being output. The

output is Nch open drain output.

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