B69000 Asiliant Technologies, B69000 Datasheet - Page 203

• Manufacturer Part Number: B69000
• Manufacturer: Asiliant Technologies

Specifications of B69000

• Lead Free Status / Rohs Status: Supplier Unconfirmed

14-36
XRAF
read/write at I/O address 3D7h with index at I/O address 3D6h set to AFh
7
6-3
2-0
XRC0
read/write at I/O address 3D7h with index at I/O address 3D6h set to C0h
Note: All four of the registers used in specifying the loop parameters for dot clock 0 (XRC0 - XRC3) must
be written, and in order from XRC0 to XRC3, before the hardware will update the synthesizer’s settings.
This is a form of double-buffering that is intended to prevent fluctuations in the synthesizer’s output as new
values are being written to these registers.
7-0
&+,36
Y-Position
Sign Bit
(0)
7
7
Cursor 2 Y-Position Sign Bit
This bit provides the sign bit of a signed 12-bit value that specifies the vertical position of cursor 2.
The magnitude bits are provided by the Cursor 2 Y-Position Low Register (XRAE) and bits 2-0 of
this register.
Reserved
These bits always return the value of 0 when read.
Cursor 2 Y-Position Magnitude Bits 10-8
These three bits provide the three most significant magnitude bits of a signed 12-bit value that
specifies the vertical position of cursor 2. The eight least significant magnitude bits of this value are
provided by bits 7-0 of the Cursor 2 Y-Position Low Register (XRAE). The sign bit is provided by
bit 7 of this register.
Dot Clock 0 VCO M-Divisort
This register provides the M-divisor, one of the loop parameters used in controlling the frequency
of the output of the synthesizer used to generate dot clock 0.A series of calculations are used to
derive this value and the values for the other loop parameters given a desired output frequency and
a series of constraints placed on different components within the synthesizer used to generate dot
clock 0. See appendix B for a detailed description of the process used to derive the loop parameter
values.
69000 Databook
Dot Clock 0 VCO M-Divisor Register
Cursor 2 Y-Position High Register
6
6
5
5
Reserved
Subject to Change Without Notice
(000:0)
Dot Clock 0 VCO M-Divisor
Extension Registers
4
4
3
3
Cursor 2 Y-Position Magnitude
2
2
Bits 10-8
(000)
Revision 1.3 8/31/98
1
1
0
0