DAC and PLL Programming
PCVisionplus
Hardware Reference
4–7
Rev 02; February 8, 2002
4.2.6.1 Feedback Sync Pulse High (HI) R/W
These bits program an additional feedback divider output but with a programmable phase, which can be selected at
Output 4. The default setting is 0x6. PCVisionplus does not use this mode of the PLL, and this register should always
be programmed to 0x0.
4.2.7 PLL Register 3 (PLLA3)
0
7
PLL Address 0x3
RDIV7
RDIV6
RDIV5
RDIV4
RDIV3
RDIV2
RDIV1
RDIV0
8
15
Reserved
Reserved
Reserved
Reserved
Reserved
REFPOL
RDIV9
RDIV8
PCR_PLLA3_16
Bit
Mnemonic
Function
9–0
RDIV
Reference Divider
10
REFPOL
Reference Polarity
15–11
Reserved
Don’t care
4.2.7.1 Reference Divider (RDIV) R/W
These bits control the PLL reference divider Modulus which divides the XTAL/EXTREF by the set modulus. The
modulus range is 1 to 1024. The modulus = RDIV + 1. The Default RDIV is 0x013 (19) and Modulus = 20. Use the
following formulas to calculate RDIV:
For PLL mode: RDIV always = 0x0 or modulus = 1
For XTAL mode: RDIV = ( 14.318 MHz / line rate )
For RS-170: line rate = 15.734 KHz.
For CCIR: line rate = 15.625 KHz.
4.2.7.2 Reference Polarity (REFPOL) R/W
This bit sets the external reference signals polarity. The default setting is 0. This bit should always be programmed to
one.
REFPOL
Function
0
Positive Edge Not Supported
1
Negative Edge always
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