CY28341-3
Byte 2: PCI Clock Register (continued)
2
1
0
1
1
1
14
12
11
PCI3
PCI2
PCI1
1 = output enabled (running). 0 = output disabled asynchronously in a low state.
1 = output enabled (running). 0 = output disabled asynchronously in a low state.
1 = output enabled (running). 0 = output disabled asynchronously in a low state.
Byte 3: AGP/Peripheral Clocks Register
Bit
@Pup
Pin#
Name
Description
24_48M
0 = pin21 output is 24MHz. Writing a '1' into this register asynchronously
changes the frequency at pin21 to 48 MHz.
7
0
21
6
5
4
3
2
1
0
1
1
0
0
1
1
1
20
21
48MHz
1 = output enabled (running). 0 = output disabled asynchronously in a low
1 = output enabled (running). 0 = output disabled asynchronously in a low
24_48M
6,7,8
6,7,8
8
DASAG1
DASAG0
AGP2
ProgrammingthesebitsallowshiftingskewoftheAGP(0:2)signalsrelative
to their default value. See Table 5.
1 = output enabled (running). 0 = output disabled asynchronously in a low
1 = output enabled (running). 0 = output disabled asynchronously in a low
1 = output enabled (running). 0 = output disabled asynchronously in a low
7
AGP1
6
AGP0
Table 5. Dial-a-Skew¥ AGP(0:2)
DASAG (1:0)
AGP(0:2) Skew Shift
00
01
10
11
Default
–280 ps
+280 ps
+480 ps
Byte 4: Peripheral Clocks Register
Bit
7
@Pup
Pin#
20
Name
Description
1 = Low strength, 0 = High strength
1
1
0
0
1
1
1
1
48M
6
21
24_48M
1 = Low strength, 0 = High strength
5
6,7,8
6,7,8
1
DARAG1
DARAG0
REF0
Programming these bits allow modifying the frequency ratio of the
AGP(2:0), PCI(6:1, F) clocks relative to the CPU clocks. See Table 6.
4
3
1 = output enabled (running). 0 = output disabled asynchronously in a low
1 = output enabled (running). 0 = output disabled asynchronously in a low
1 = Low strength, 0 = High strength
2
56
REF1
1
1
REF0
0
56
REF1
1 = Low strength, 0 = High strength (K7 Mode only)
Table 6. Dial-A-Ratio¥ AGP(0:2)
DARAG (1:0)
CU/AGP Ratio
00
01
10
11
Frequency Selection Default
2/1
2.5/1
3/1
Byte 5: SDR/DDR Clock Register
Bit
@Pup
Pin#
Name
BUF_IN
Description
7
0
45
DDR Mode, BUF_IN threshold setting. 0 = 1.15V, 1 = 1.05V
threshold
voltage
6
5
1
1
46
FBOUT
1 = output enabled (running). 0 = output disabled asynchronously in a low state.
1 = output enabled (running). 0 = output disabled asynchronously in a low state.
29,30 DDRT/C5
Rev 1.0,November 21, 2006
Page 6 of 19
SPECTRALINEAR [ SPECTRALINEAR INC ]
