stlc5412 STMicroelectronics, stlc5412 Datasheet - Page 15

• Manufacturer Part Number: stlc5412
• Description: 2b1q U Interface Device Enhanced With Dect Mode
• Manufacturer: STMicroelectronics

To read a 12 bits message, the difference is:
limited address field:
extended data field (D11 - D8): A3 - A0.
The Write/Read back indicator doesn‘t exit.
DIGITAL SYSTEM INTERFACE
Two B channels, each at 64 kbit/s and one D chan-
nel at 16 kbit/s form the Basic access data. Basic
access data is transferred on the Digital System In-
terface with several different formats selectable by
means of the configuration register CR1.
The DSI is basically constituted of 5 wires (see
fig.2 and 3):
It is possible to separate the D channel from the B
channels and to transfer it on a separate Digital
Interface constituted of 2 pins:
The TDM (Time Division Multiplex) mode uses
the same bit and frame clocks as for the B chan-
nels. The continuous mode uses an internally
generated 16 kHz bit clock output:
For all formats when D channel port is enabled
”continuous mode” is possible. When the D chan-
nel port is enabled in TDM mode, D bits are as-
signed according to the related format on Dx and
Dr .
STLC5412 provides a choice of four multiplexed
formats for the B and D channels data as shown
in fig.2 and 3.
Format 1: the 2B+D data transfer is assigned to
the first 18 bits of the frame on Br and Bx I/0 pins.
Channels are assigned as follows: B1(8 bits),
B2(8 bits), D(2 bits), with the remaining bits ig-
nored until the next Frame sync pulse.
Format 2: the 2B+D data transfer is assigned to
the first 19 bits of the frame on Br and Bx I/O
pins. Channels are assigned as follows: B1(8
bits), D(1 bit), 1 bit ignored, B2(8 bits), D(1 bit),
with the remaining bits ignored until the next
frame sync pulse.
Format 3: B1 and B2 Channels can be inde-
pendently assigned to any 8 bits wide time slot
among 64 (or less) on the Bx and Br pins. The
transmit and receive directions are also inde-
pendent. When TDM mode is selected, the D
channel can be assigned to any 2 bits wide time
slot among 256 on the Bx and Br pins or on the
BCLK
Bx
Br
FSa
FSb
Dx
Dr
DCLK D channel clock output
bit clock
data input to transmit to the line
data output received from the line
Transmit Frame sync
Receive Frame sync
D channel data input
D channel data ouput
A7 - A4
Dx and Dr pins (D port disabled or enabled in
TDM mode respectively).
Format 4: is a GCI like format excluding Monitor
channel and C/I channel. The 2B+D data transfer
is assigned to the first 26 bits of the frame on Br
and Bx I/O pins. Channels are assigned as fol-
lows. B1(8 bits) B2(8 bits), 8 bits ignored, D(2
bits), with remaining bits ignored up to the next
frame sync pulse.
When the Digital Interface clocks are selected as
inputs, FSa must be a 8 kHz clock input which in-
dicates the start of the frame on the data input pin
Bx. When the Digital Interface clocks are selected
as outputs, FSa is an 8 kHz output pulse con-
forming to the selected format which indicates
the frame beginning for both Tx and Rx direc-
tions.
When the Digital Interface clocks are selected as
inputs, FSb is a 8 kHz clock input which defines
the start of the frame on the data ouput pin Br.
When the Digital Interface clocks are selected as
outputs, FSb is a 8 kHz output pulse indicating
the second 64kbit/s slot.
Two phase-relations between the rising edge of
FSa/FSb and the first (or second for FSb as out-
put) slot of the frame can be selected depending
on format selected: Delayed timing mode or non
Delayed timing mode.
Non delayed data mode is similar to long frame
timing on the COMBOI/II series of devices: The
first bit of the frame begins nominally coincident
with the rising edge of FSa/b. When output, FSa
is coincident with the first 8 bits wide time-slot
while FSb is coincident with the second 8 bits
wide time-slot. Non delayed mode is not available
in format 2.
Delayed timing mode, which is similar to short
frame sync timing on COMBO I/II, in which the
FSa/b input must be set high at least a half cycle
of BCLK earlier the frame beginning. When out-
put, FSa 1bit wide pulse indicates the first 8 bits
wide time-slot while FSb indicates the second.
Delayed mode is not available in format 4.
2B+D basic access data to transmit to the line
can be shifted in at the BCLK frequency on the
falling edges during the assigned time-slots.
When D channel port is enabled, only B1 & B2
data is shifted in during the assigned time slots. In
format 4, data is shifted in at half the BCLK fre-
quency on the receive falling edges.
2B+ D basic access data received from the line
can be shifted out from the Br output at the BCLK
frequency on the rising edges during the assigned
time-slots. Elsewhere, Br is in the high impedance
state. When the D channel port is enabled, only
B1 & B2 data is shifted out from Br. In Format 4,
data is shifted out at half the BCLK frequency on
the transmit rising edges; there is 1.5 period delay
between the rising transmit edge and the receive
falling edge of BCLK.
STLC5412
15/74