TX4939XBG-400 Toshiba, TX4939XBG-400 Datasheet - Page 571

• 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

SIO
19.3.3. Serial Clock Generator
Generates the Serial Clock (SIOCLK). SIOCLK determines the serial transfer rate and has a frequency that is 16× the baud
rate. One of the following can be selected as the source for the Serial Clock (SIOCLK).
The IMBUSCLK frequency can be selected from frequencies that are 1/4, 1/6, 1/10, or 1/12 the frequency of the CPU clock.
SCLK0 (baud rate clock0) is generated by TX4939 Audio Clock Generator with a frequency of 14.7456Mhz. SCLK1 (baud
rate clock1) is generated using ATA100 clock by the Master Clock Generator with a frequency of 14.7465Mhz. Please refer
to Chapter 5. Clock Generators for SCLK0, SCLK1 (baud rate clocks) generation information.
The baud rate generator is a circuit that divides these clock signals according to the following formula.
Table 19-2 and Table 19-3 gives example settings of divide values relative to representative baud rates. Figure 19-3 shows
the block diagram of the baud rate generator used to generate SIOCLK.
It is possible to correctly receive data if the error of the baud rate set by this controller is within 3.12 % of the target baud rate
(communication baud rate).
Rev. 3.1 November 1, 2005
IMBUSCLK
fc: Clock frequency of IMBUSCLK or Clock frequency of SCLK0,SCLK1
Prescalar Value: 2, 8, 32, 128
Divide Value: 1, 2, 3,…255
SCLK0
SCLK1
Internal System Clock (IMBUSCLK)
Internal Baud rate Clock0 (SCLK0)
Internal Baud rate Clock1 (SCLK1)
Baud rate generator circuit output
SILCR. SCS [2:1]
Select SIOCLK
Baud Rate=
Selector
Figure 19-3 Baud Rate Generator and SIOCLK Generator
fc
Prescale
Prescalar
1/128
1/32
1/2
1/8
x
f
Divisor
c
T0
T2
T4
T6
Baud Rate Generator
SIBGR. BCLK
19-5
x
Select CLK
16
Selector
SIBGR. BRD
Divide value
1/1 − 1/255
Baud Rate
Divider
Toshiba RISC Processor
SILCR. SCS [0]
Select SIOCLK
Selector
TX4939
SIOCLK
19
19