TX4939XBG-400 Toshiba, TX4939XBG-400 Datasheet - Page 272

• 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

TMR
13.3. Detailed Explanation
13.3.1. Overview
The TX4939 has an on-chip 6-channel 32-bit timer/counter. Each channel supports the following modes.
13.3.2. Counter Clock
The clock used for counting can be set to a frequency that is 1/2, 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, or 1/256 of the internal
clock (IMBUSCLK) frequency, or can be selected from nine counter input signal (TCLK) types. Divide Register n
(TMCCDRn) and the Counter Clock Select bit (TMTCRn.CCS) are used to select the counter clock. In this situation,
IMBUSCLK is the internal clock signal which is the G-Bus clock divided by 2. See “Chapter 5 Clock Generator” for more
information.
The counter input signal (TCLK) is used by three channels. Using TCLK makes it possible to count external events. The
External Clock Edge bit (TMTCRn.ECES) can be used to select the clock rising/falling count.
Set the TCLK clock frequency to 45% or less of IMBUSCLK (TCLK = 22.5 MHz or less when IMBUSCLK = 50 MHz). The
following table shows example count times when using 50 MHz IMBUSCLK.
Rev. 3.1 November 1, 2005
2
4
8
16
32
64
128
256
Interval Timer Mode (Timer 0, 1, 2, 3, 4, 5)
This mode periodically generates interrupts.
Pulse Generator Mode (Timer 0, 1)
This is the pulse signal output mode.
Watchdog Timer Mode (Timer 2)
This mode is used to monitor system abnormalities.
Note that TX4939 does not support TCLK.
Divide
Rate
000
001
010
011
100
101
110
111
TMCCDRn.
CCD
Table 13-1 Divide Value and Count (IMBUSCLK = 100 MHz)
50.0 M
25.0 M
12.5 M
6.25 M
3.125 M
1.5625 K
781.25 K
390.625 K
Frequency (Hz)
Counter Clock
13-4
20.00
40.00
80.00
160.00
320.00
640.00
1280.00
2560.00
Resolution (ns) Max. Set Time
85.90
171.80
343.60
687.19
1374.39
2748.78
5497.56
10995.12
(sec.)
Toshiba RISC Processor
50000000
25000000
12500000
6250000
3125000
1562500
781250
390625
TMCPRAn Value
for 1 sec.
TX4939
13
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