TX4939XBG-400 Toshiba, TX4939XBG-400 Datasheet - Page 101

• Manufacturer Part Number: TX4939XBG-400
• Manufacturer: Toshiba

Specifications of TX4939XBG-400

• Cpu Core: TX49/H4 90nm
• Clock Mhz/max Mips: 400/520
• Inst./data Cache: 32KB (4 Way)/32KB (4 Way)
• Tlb: x
• 1cycle Mac: x
• Volts (v): 1.25/2.5/3.3
• Peripherals: DDR, NAND, ATA, ETHERNET, SECURITY, FPU, MMU, SPI, I2S, I2C, PCI, VIDEO, UART, TIMER, RTC
• Companion Chip: TC86C001FG
• Package: PGBA456

CG
5.3.4. Restriction of Audio Clock for Over Sampling
Since a digital clock multiplier is used, i.e. mdgen_32_147 in Figure 5-3 Diagram of Audio Clock Generator, the source
clock, 451.584 MHz or 338.688 MHz has intrinsic jitter.
Note that this mdgen_32_147 is used to generate the source clock for 96KHz, 48KHz, 32KHz, 24KHz, 16KHz, and 8KHz
Fs frequency. These clocks might be affected and not for 88.2KHz neither 44.1KHz.
Table 5-5 mdgen_32_147 Operation explains the operation of multiplier/divider. The mdgen_32_147 counts the input clock,
i.e. 451.584 MHz and the counter value will return to zero when it reaches 147. Output pulse will be generated 32 times
within every 147 count cycles. The column “SEQ” means the cycle number of 32 output clocks. The column “Real Value”
is the theoretical figure of clock timing. Actual clock is generated at the timing displayed at the column “Pseudo”. The
column “Error” shows the difference between theoretical and actual value.
These errors are considered as jitter in the clock.
by series of divide by 2.
at the normal over sampling timing.
Next page shows detail of this jitter.
Rev. 3.1 November 1, 2005
For example, the jitter will disappear at 32fs for 96KHz sampling. This jitter may not affect sampling operation
But it might affect the operation of Analog-Digital conversion with Sigma-Delta system.
SEQ
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
0
1
2
3
4
5
6
7
8
9
Table 5-5 mdgen_32_147 Operation
This multiplication factor is power of 2, these jitter will be disappeared after dividing
Real Value
101.0625
105.6563
110.2500
114.8438
119.4375
124.0313
128.6250
133.2188
137.8125
142.4063
147.0000
13.7813
18.3750
22.9688
27.5625
32.1563
36.7500
41.3438
45.9375
50.5313
55.1250
59.7188
64.3125
68.9063
73.5000
78.0938
82.6875
87.2813
91.8750
96.4688
0.0000
4.5938
9.1875
5-7
Pseudo
101
106
110
115
119
124
129
133
138
142
147
14
18
23
28
32
37
41
46
51
55
60
64
69
74
78
83
87
92
96
0
5
9
Error
-0.90 ns
-0.48 ns
-0.07 ns
-0.97 ns
-0.55 ns
-0.14 ns
-1.04 ns
-0.62 ns
-0.21 ns
-1.11 ns
-0.69 ns
-0.28 ns
-0.76 ns
-0.35 ns
-0.83 ns
-0.42 ns
0.00 ns
0.42 ns
0.83 ns
0.35 ns
0.76 ns
0.28 ns
0.69 ns
0.21 ns
0.62 ns
1.04 ns
0.14 ns
0.55 ns
0.97 ns
0.07 ns
0.48 ns
0.90 ns
0.00 ns
Toshiba RISC Processor
TX4939
5
5
5
5