ST75951 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'ST75951' PDF : 21 Pages View PDF
ST75951
FUNCTIONAL DESCRIPTION (continued)
Figure 11 : GPIO0 When bit6 = ’1’ in REG2
GPIO0
GPIO0
REG 2 - BIT1
SETTING
F0/N
Figure 12 : GPIO3 When bit10 = ’1’ in REG2
GPIO3
F0
GPIO3
REG 2 - BIT4
SETTING
GPIO1 and GPIO2 are dedicated input and control
CLID and OFF-HOOK function respectively if the
control input Pin HM is set to ’1’.
Table 2
HM GPIO1 GPIO2
Function
1
0
0
ON-HOOK
1
0
1
OFF-HOOK
1
1
0
CLID
1
1
1
SPECIAL
HM
CL
OH
Function
0
0
0
ON-HOOK
0
0
1
OFF-HOOK
0
1
0
CLID
0
1
1
SPECIAL
CL, OH : Bit 2, 3 Reg 3.
Depending of the setting of the Mask bit in control
register 1, any change of non-masked GPIO can
generate an interrupt to the processor thanks to
GPI (General purpose Interrupt).
7 - Operating Modes
Three operating modes controlled either by the
GPIO1 and 2 or by the control register 3 are imple-
mented :
- ON-HOOK,
- OFF-HOOK,
- CLID (Caller ID).
VDD
PP
VDD
PP
Figure 13
D5
D6
7.1 - ON-HOOK
During ON-HOOK state no signal is sent by D5, D6.
D5 = D6 = VDD.
Ring
When in ON-HOOK state, the ST952 sends a
1MHz differential signal on D3, D4 when it re-
ceives an incoming ringing signal from Tip/Ring.
ST75951 will output on RING Pin the image of the
ring signal (RING Pin is also duplicated in the read
register 2 bit 5) (see Figure 15).
7.2 - OFF-HOOK
Depending on Pin HM status (see Table 2), 2 pos-
sibilities are offered to control the device to go in
OFF-HOOK state.
Figure 14
D5
VDD
F0
D6
VDD
F0
D5 and D6 send F0 clock in opposite phase to
ST952.
10/21
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