TMS37122 Datasheet, PDF (34/73 Pages) Texas Instruments – TIRIS Automotive Devices Analog Front End IC TMS37122

Analog Front End IC TMS37122 - Reference Guide
August ’01
Figure 20: Default Memory Content
Bit 3
NO
CL₀KA
4
NO NO
W₀DE3
WDE2
0
Bit 0
NO
WA₁KE
3
Bit 3
Bit 0 Bit 3
PPM THRESHOLD
01111
C_TELEGR
000000000
C_WAIT
000000000
NIBBLE
2
Bit 0 Bit 3
VWAKE B/ 2/3
1111
1
Bit 0 Bit 3
VWAKE B/ 1
1111
PASSIVE ENTRY WAKE PATTERN
00000000
PASSIVE START WAKE PATTERN
00000000
0
VWAKE A/ 1
11
00
00
Bit 0
1⁰
0¹
0²
ROW
Bit 3
Bit 0 Bit 15
Bit 0
3DMEMD4.DRW
The default PPM Threshold is configured for a medium data rate of 2kBit/s, realized for ex-
ample with a low bit period of tbitL=400 and a high bit period of tbitH=600µs (see Figure
12). It is assumed that toff is as short as possible (toff<=100µs), but still achieving 50% mod-
ulation (m=33%) under all conditions. Under this assumptions CLKA is available continu-
ously or interrupted only shortly during toff. If this cannot be achieved due to lower quality
factors and thereore stronger damping, or if higher data rates are demanded, PPM Threshold
must be adapted.
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