sm8211m Nippon Precision Circuits Inc, (NPC), sm8211m Datasheet - Page 8

• Manufacturer Part Number: sm8211m
• Description: Pocsag Decoder For Pagers
• Manufacturer: Nippon Precision Circuits Inc, (NPC)

Operating Modes
The SM8211M has four operating modes—Switch-
ON, Preamble, Idle and Lock modes. Note that all
values in parentheses in the following figures are for
the case when the speed is 1200 bps.
Switch-ON mode
After power is applied and after RST has gone LOW
to reset all internal circuits, code words for the 27-bit
flag data and the six 18-bit addresses are received
from the CPU on TX-DATA and are stored. As each
code word comprises 32 bits, this process takes (32
(BS2 flag = 0)
(BS2 flag = 1)
TX-DATA
TX-CLK
RST
BS1
BS2
BS2
BS3
X > 2 ms for external system clock operation or during continuous oscillations
X > 900 ms for internal oscillator operation immediately after power is applied or BACKUP is released (V
X > 1.5 s for internal oscillator operation immediately after power is applied or BACKUP is released (V
1 to 200 ms
X
Figure 3. Switch-ON mode timing
1
2
SM8211M
224
7) + 1 TX-CLK cycles to complete. When the 225
TX-CLK cycles have been received, BS1, BS2 and
BS3 are set and device operation transfers to pream-
ble mode.
225
(0.833 x M ms)
1.953 x M ms
127 ms (54.2 ms)
NIPPON PRECISION CIRCUITS—8
(0.833 x N ms)
1.953 x N ms
DD
DD
< 1.5 V)
= 1.5 to 3.5 V)
Preamble mode