Chapter 12 Timer/Counter
12-3
12.3 Detailed
Explanation
12.3.1 Overview
The TX4925 has an on-chip 3-channel 32-bit timer/counter. Each channel supports the following
modes.
(1) Interval Timer Mode (Timer 0, 1, 2)
This mode periodically generates interrupts.
(2) Pulse Generator Mode (Timer 0, 1)
This is the pulse signal output mode.
(3) Watchdog Timer Mode (Timer 2)
This mode is used to monitor system abnormalities.
12.3.2 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 6 Clocks” 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 = 18 MHz or less when
IMBUSCLK = 40 MHz). The following table shows example count times when using 40 MHz
IMBUSCLK.
Table 12.3.1 Divide Value and Count (IMBUSCLK = 40 MHz)
Divide
Rate
TMCCDRn.
CCD
Counter Clock
Frequency (Hz)
Resolution (ns)
Max. Set Time
(sec.)
TMCPRAn Value
for 1 sec.
2
4
8
16
32
64
128
256
000
001
010
011
100
101
110
111
20.0 M
10.0 M
5.0 M
2.5 M
1.25 M
625.0 K
312.5 K
156.25 K
50.00
100.00
200.00
400.00
800.00
1600.00
3200.00
6400.00
214.75
429.50
858.99
1717.99
3435.97
6871.95
13743.90
27487.79
20000000
10000000
5000000
2500000
1250000
625000
312500
156250
Содержание TMPR4925
Страница 1: ...64 Bit TX System RISC TX49 Family TMPR4925 Rev 3 0 ...
Страница 4: ......
Страница 15: ...Handling Precautions ...
Страница 16: ......
Страница 18: ...1 Using Toshiba Semiconductors Safely 1 2 ...
Страница 40: ...3 General Safety Precautions and Usage Considerations 3 18 ...
Страница 42: ...4 Precautions and Usage Considerations 4 2 ...
Страница 43: ...TMPR4925 ...
Страница 44: ......
Страница 54: ...Chapter 1 Features 1 8 ...
Страница 58: ...Chapter 2 Block Diagram 2 4 ...
Страница 88: ...Chapter 4 Address Mapping 4 12 ...
Страница 226: ...Chapter 8 DMA Controller 8 58 ...
Страница 260: ...Chapter 9 SDRAM Controller 9 34 ...
Страница 480: ...Chapter 15 Interrupt Controller 15 32 ...
Страница 554: ...Chapter 19 Real Time Clock RTC 19 8 ...
Страница 555: ...Chapter 20 Removed 20 1 20 Removed ...
Страница 556: ...Chapter 20 Removed 20 2 ...
Страница 564: ...Chapter 21 Extended EJTAG Interface 21 8 ...
Страница 580: ...Chapter 22 Electrical Characteristics 22 16 ...
Страница 586: ...Chapter 23 Pin Layout Package 23 6 23 2 Package Package Type Package Code 256 pin PBGA PBGA 4L P BGA256 2727 1 27A4 ...
Страница 588: ...Chapter 24 Usage Notes 24 2 ...
Страница 590: ...Appendix A TX49 H2 Core Supplement A 2 ...