STPCD01 STMicroelectronics, STPCD01 Datasheet - Page 20

• Manufacturer Part Number: STPCD01
• Description: STPC CLIENT DATASHEET - PC COMPATIBLE EMBEDED MICROPROCESSOR
• Manufacturer: STMicroelectronics

PIN DESCRIPTION
ISACLK and ISACLKX2 as the input selection
strobes.
DREQ_MUX[1:0] ISA Bus Multiplexed DMA Re-
quest. These are the ISA bus DMA request sig-
nals. They are to be encoded before connection to
the STPC Client using ISACLK and ISACLKX2 as
the input selection strobes.
DACK_ENC[2:0] DMA Acknowledge. These are
the ISA bus DMA acknowledge signals. They are
encoded by the STPC Client before output and
should be decoded externally using ISACLK and
ISACLKX2 as the control strobes.
TC ISA Terminal Count. This is the terminal count
output of the DMA controller and is connected to
the TC line of the ISA bus. It is asserted during the
last DMA transfer, when the Byte count expires.
2.2.12. MONITOR INTERFACE
RED, GREEN, BLUE RGB Video Outputs. These
are the 3 analog color outputs from the RAM-
DACs. These signals are sensitive to interference,
therefore they need to be properly shielded.
VSYNC Vertical Synchronization Pulse. This is
the vertical synchronization signal from the VGA
controller.
HSYNC Horizontal Synchronization Pulse. This is
the horizontal synchronization signal from the
VGA controller.
VREF_DAC DAC Voltage reference. An external
voltage reference is connected to this pin to bias
the DAC.
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Issue 2.2 - October 13, 2000
RSET Resistor Current Set. This reference cur-
rent input to the RAMDAC is used to set the full-
scale output of the RAMDAC.
COMP Compensation. This is the RAMDAC com-
pensation pin. Normally, an external capacitor
(typically 10nF) is connected between this pin and
V
DDC[1:0] Direct Data Channel Serial Link. These
bidirectional pins are connected to CRTC register
3Fh to implement DDC capabilities. They conform
to I
collector output drivers which are internally con-
nected to V
They can instead be used for accessing I C devic-
es on board. DDC1 and DDC0 correspond to SCL
and SDA respectively.
2.2.13. MISCELLANEOUS
ST[6], Reserved.
ST[5] This is used for speaker output.
ST[4] Reserved.
ST[3:0] The pins are for testing the STPC. The
default settings on these pins should be 1111 for
the STPC to function correctly. By setting the
ST[3:0] to 0111, the STPC is tristated.
CLKDEL[2:0] Reserved . The pins are reserved
for Test and Miscellaneous functions)
DD
2
C electrical specifications, they have open-
to damp oscillations.
DD
through pull-up resistors.