Intel 6300ESB ICH, Design Manual

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January 2007 205
Intel
®
855GME Chipset and Intel
®
6300ESB ICH Embedded Platform Design Guide
Intel
®
6300ESB Design Guidelines
9.4.2.1 Valid Codec Configurations
Table 79 describes the valid codec configurations.
9.4.3 SPKR Pin Consideration
SPKR is used as both the output signal to the system speaker and as a functional strap. The strap
function enables or disables the TCO Timer Reboot function based on the state of the SPKR pin on
the rising edge of PWROK. When enabled, the 6300ESB sends an SMI# to the processor upon a
TCO timer time out. The status of this strap is readable through the NO_REBOOT bit (bit 1, D31:
F0, Offset D4h). The SPKR signal has a weak integrated pull-down resistor (the resistor is only
enabled during boot/reset). Therefore, its default state is a logical zero or set to reboot. To disable
the feature, a jumper may be populated to pull the signal line high (see
Figure 103 ). The value of
the pull-up must be such that the voltage divider output caused by the pull-up, the effective
pull-down (R
eff
), and the 6300ESB’s integrated pull-down resistor will be read as logic high
(0.5 V
CC
3.3 to V
CC
3.3 + 0.5 V).
Table 79. Supported Codec Configurations
Option Primary Codec Secondary Codec Tertiary Codec
1 Audio Audio Audio
2 Audio Audio Modem
3 Audio Audio Audio/Modem
4 Audio Modem Audio
5 Audio Audio/Modem Audio
6 Audio/Modem Audio Audio
7 Modem - -
NOTE: For power management reasons, codec power management registers are in audio
space. As a result, when there is an audio codec in the system it must be Primary. In
addition, there cannot be two modems in a system since there is only one set of
modem DMA channels.
Figure 103. Example Speaker Circuit