参数资料
型号: ST6242BQ1/XXX
厂商: STMICROELECTRONICS
元件分类: 微控制器/微处理器
英文描述: 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PQFP64
封装: PLASTIC, QFP-64
文件页数: 31/69页
文件大小: 1846K
代理商: ST6242BQ1/XXX
Obsolete
Product(s)
- Obsolete
Product(s)
Obsolete
Product(s)
- Obsolete
Product(s)
37/69
ST62T42B/E42B
4.2 TIMER 1 & 2
The MCU features two on-chip Timer peripheral
named TIMER 1 & TIMER 2. Each of these timers
consist of an 8-bit counter with a 7-bit programma-
ble prescaler, giving a maximum count of 215.
The content of the 8-bit counter can be read/writ-
ten in the Timer/Counter register, TCR, while the
state of the 7-bit prescaler can be read in the PSC
register. The control logic device is managed in
the TSCR register as described in the following
paragraphs.
The 8-bit counter is decremented by the output
(rising edge) coming from the 7-bit prescaler and
can be loaded and read under program control.
When it decrements to zero then the TMZ (Timer
Zero) bit in the TSCR is set to “1”. If the ETI (Ena-
ble Timer Interrupt) bit in the TSCR is also set to
“1”, an interrupt request is generated as described
in the Interrupt Chapter. The Timer interrupt can
be used to exit the MCU from WAIT mode.
The prescaler input is the internal frequency fINT
divided by 12 (TIMER 1 & 2). The prescaler decre-
ments on the rising edge. Depending on the divi-
sion factor programmed by PS2, PS1 and PS0 bits
in the TSCR. The clock input of the timer/counter
register is multiplexed to different sources. For di-
vision factor 1, the clock input of the prescaler is
also that of timer/counter; for factor 2, bit 0 of the
prescaler register is connected to the clock input of
TCR. This bit changes its state at half the frequen-
cy of the prescaler input clock. For factor 4, bit 1 of
the PSC is connected to the clock input of TCR,
and so forth. The prescaler initialize bit, PSI, in the
TSCR register must be set to “1” to allow the pres-
caler (and hence the counter) to start. If it is
cleared to “0”, all the prescaler bits are set to “1”
and the counter is inhibited from counting. The
prescaler can be loaded with any value between 0
and 7Fh, if bit PSI is set to “1”. The prescaler tap is
selected by means of the PS2/PS1/PS0 bits in the
control register.
Figure 20 illustrates the Timer’s working principle.
Figure 20. Timer Working Principle
BIT0
BIT1
BIT2
BIT3
BIT6
BIT5
BIT4
CLOCK
7-BIT PRESCALER
8-1 MULTIPLEXER
8-BIT COUNTER
BIT0
BIT1
BIT2
BIT3
BIT4
BIT5
BIT6
BIT7
1
0
2
3
4
5
6
7
PS0
PS1
PS2
VA00186
37
相关PDF资料
PDF描述
ST6246BB6/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PDIP56
ST6260BB6 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PDIP20
ST6294B8/XXX 8-BIT, MROM, 8 MHz, MICROCONTROLLER, PDIP28
ST62T94B8 8-BIT, OTPROM, 8 MHz, MICROCONTROLLER, PDIP28
ST62E85BG1 8-BIT, UVPROM, 8 MHz, MICROCONTROLLER, CQFP80
相关代理商/技术参数
参数描述
ST6242BQ6 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:8-BIT OTP/EPROM MCU WITH LCD DRIVER, EEPROM AND A/D CONVERTER
ST6242BQ6/XXX 制造商:未知厂家 制造商全称:未知厂家 功能描述:8-Bit Microcontroller
ST6242-P/QFP 功能描述:插座和适配器 ST62 P/QFP Adaptor RoHS:否 制造商:Silicon Labs 产品:Adapter 用于:EM35x
ST6242Q1/XX 制造商:未知厂家 制造商全称:未知厂家 功能描述:8-Bit Microcontroller
ST6242Q6/XX 制造商:未知厂家 制造商全称:未知厂家 功能描述:8-Bit Microcontroller