參數(shù)資料
型號： uPSD3251
廠商： 意法半導(dǎo)體
英文描述： Flash Programmable System Devices with 8032 Microcontroller Core(帶8032微控制器內(nèi)核的Flash可編程系統(tǒng)設(shè)備)
中文描述： 閃存可編程系統(tǒng)設(shè)備與8032微控制器內(nèi)核（帶8032微控制器內(nèi)核的閃存可編程系統(tǒng)設(shè)備）
文件頁數(shù)： 57/128頁
文件大?。?/td> 1566K
代理商： UPSD3251
57/128
μPSD3251F
Baud Rates.
The baud rate in Mode 0 is fixed:
Mode 0 Baud Rate = f
OSC
/ 12
The baud rate in Mode 2 depends on the value of
Bit SMOD = 0 (which is the value on reset), the
baud rate is 1/64 the oscillator frequency. If SMOD
= 1, the baud rate is 1/32 the oscillator frequency.
Mode 2 Baud Rate = (2
SMOD
/ 64) x f
OSC
In the μPSD3251F device, the baud rates in
Modes 1 and 3 are determined by the Timer 1
overflow rate.
Using Timer 1 to Generate Baud Rates.
When
Timer 1 is used as the baud rate generator, the
baud rates in Modes 1 and 3 are determined by
the Timer 1 overflow rate and the value of SMOD
as follows (see Table 44, page 58):
Mode 1,3 Baud Rate =
(2
SMOD
/ 32) x (Timer 1 overflow rate)
The Timer 1 Interrupt should be disabled in this
application. The Timer itself can be configured for
either
“
timer
”
or
“
counter
”
operation, and in any of
its 3 running modes. In the most typical applica-
tions, it is configured for
“
timer
”
operation, in the
Auto-reload Mode (high nibble of TMOD = 0010B).
In that case the baud rate is given by the formula:
Mode 1,3 Baud Rate =
(2
SMOD
/ 32) x (f
OSC
/ (12 x [256
–
(TH1)]))
One can achieve very low baud rates with Timer 1
by leaving the Timer 1 Interrupt enabled, and con-
figuring the Timer to run as a 16-bit timer (high nib-
ble of TMOD = 0001B), and using the Timer 1
Interrupt to do a 16-bit software reload. Figure 20
lists various commonly used baud rates and how
they can be obtained from Timer 1.
Using Timer/Counter 2 to Generate Baud
Rates.
In the μPSD3251F device, Timer 2 select-
ed as the baud rate generator by setting TCLK
and/or RCLK (see Figure 20, page 49 Timer/
Counter 2 Control Register (T2CON)).
Note:
The baud rate for transmit and receive can
be simultaneously different. Setting RCLK and/or
TCLK puts Timer into its Baud Rate Generator
Mode.
The RCLK and TCLK Bits in the T2CON register
configure UART 1. The RCLK1 and TCLK1 Bits in
the PCON register configure UART 2.
The Baud Rate Generator Mode is similar to the
Auto-reload Mode, in that a roll over in TH2 causes
the Timer 2 registers to be reloaded with the 16-bit
value in registers RCAP2H and RCAP2L, which
are preset by software.
Now, the baud rates in Modes 1 and 3 are deter-
mined at Timer 2
’
s overflow rate as follows:
Mode 1,3 Baud Rate = Timer 2 Overflow Rate / 16
The timer can be configured for either
“
timer
”
or
“
counter
”
operation. In the most typical applica-
tions, it is configured for
“
timer
”
operation (C/T2 =
0).
“
Timer
”
operation is a little different for Timer 2
when it
’
s being used as a baud rate generator.
Normally, as a timer it would increment every ma-
chine cycle (thus at the 1/6 the CPU clock frequen-
cy). In the case, the baud rate is given by the
formula:
Mode 1,3 Baud Rate = f
OSC
/ (32 x [65536 -
(RCAP2H, RCAP2L)]
where (RCAP2H, RCAP2L) is the content of
RC2H and RC2L taken as a 16-bit unsigned inte-
ger.
Timer 2 also be used as the Baud Rate Generating
Mode. This mode is valid only if RCLK + TCLK = 1
in T2CON or in PCON.
Note:
A roll-over in TH2 does not set TF2, and will
not generate an interrupt. Therefore, the Timer in-
terrupt does not have to be disabled when Timer 2
is in the Baud Rate Generator Mode.
Note:
If EXEN2 is set, a 1-to-0 transition in T2EX
will set EXF2 but will not cause a reload from
(RCAP2H, RCAP2L) to (TH2, TL2). Thus when
Timer 2 is in use as a baud rate generator, T2EX
can be used as an extra external interrupt, if de-
sired.
It should be noted that when Timer 2 is running
(TR2 = 1) in
“
timer
”
function in the Baud Rate Gen-
erator Mode, one should not try to READ or
WRITE TH2 or TL2. Under these conditions the
timer is being incremented every state time, and
the results of a READ or WRITE may not be accu-
rate. The RC registers may be read, but should not
be written to, because a WRITE might overlap a
reload and cause WRITE and/or reload errors.
Turn the timer off (clear TR2) before accessing the
Timer 2 or RC registers, in this case.
相關(guān)PDF資料
PDF描述
uPSD3253AV-24T1T Flash Programmable System Devices with 8032 Microcontroller Core
UPSD3253B Two and Three Channel Codewheels
UPSD3253BV Flash Programmable System Devices with 8032 Microcontroller Core
uPSD3254B-24T1T Flash Programmable System Devices with 8032 Microcontroller Core
uPSD3254B-40T6T Flash Programmable System Devices with 8032 Microcontroller Core
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
uPSD3251MEB 制造商:P&S 功能描述:Flash Programmable System Devices with 8032 Microcontroller Core 制造商:STMicroelectronics 功能描述:Flash Programmable System Devices with 8032 Microcontroller Core
UPSD3253 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Devices with 8032 Microcontroller Core and 256Kbit SRAM
UPSD3253A-24T1 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Device with 8032 Microcontroller Core
UPSD3253A-24T1T 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Device with 8032 Microcontroller Core
UPSD3253A-24T6 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash Programmable System Device with 8032 Microcontroller Core
發(fā)布緊急采購，3分鐘左右您將得到回復(fù)。

采購需求

(若只采購一條型號，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

發(fā)布成功！您可以繼續(xù)發(fā)布采購。也可以進入我的后臺，查看報價

*型號 *數(shù)量 廠商 批號 封裝
添加更多采購

我的聯(lián)系方式

*
*
*