STPCI01 STMicroelectronics, STPCI01 Datasheet - Page 32

• Manufacturer Part Number: STPCI01
• Description: STPC INDUSTRIAL - PC COMPATIBLE EMBEDED MICROPROC
• Manufacturer: STMicroelectronics

STRAP OPTION
3.1.3. STRAP REGISTER 2
Bits 4-0 of this register reflect the status of pins MD[20:16] respectively. Bit 5 of this register reflect the sta-
tus of pin MD[23]. Bit 4 is writeable, writes to other bits in this register have no effect.
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Strap2
Bit Number Sampled
7
Bits 7-5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
This register defaults to the values sampled on MD[23] and MD[20:16] pins after reset
Rsv
6
Mnemonic
MD20
MD19
MD18
MD17
Rsv
Rsv
5
Issue 2.4 - February 11, 2002
Access = 0022h/0023h
Description
an input, setting to ’1’: Internal. HCLK pin is an output and is connected
to the internal frequency synthesizer output.
This bit reflects the value sampled on MD[17] pin and controls the PCI
clock output as follows:
Setting to ’0’, the PCI clock output = HCLK / 3
Reserved.
Reserved.
This bit reflects the value sampled on MD[20] pin and controls the Dot
clock (DCLK) source. Note This bit is writeable as well as readable.
This bit reflects the value sampled on MD[19] pin and controls the
Graphics clock source.
This bit reflects the value sampled on MD[18] pin and controls the
Host/CPU clock source as follows: setting to ’0’: External. HCLK pin is
Setting to ’1’, the PCI clock output = HCLK / 2.
MD20
4
MD19
3
MD18
2
MD17
1
Regoffset = 04Ch
Rsv
0