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參數(shù)資料
| 型號： | PCA9551 |
| 廠商： | NXP Semiconductors N.V. |
| 元件分類： | LED驅(qū)動器 |
| 英文描述： | 8-bit I2C LED driver with programmable blink rates |
| 中文描述： | 8位I2C LED與可編程閃爍率司機(jī) |
| 文件頁數(shù)： | 5/21頁 |
| 文件大?。?/td> | 161K |
| 代理商： | PCA9551 |
Philips Semiconductors
Product data sheet
PCA9551
8-bit I
2
C LED driver with programmable blink rates
2004 Oct 01
5
DEVICE ADDRESSING
Following a START condition the bus master must output the
address of the slave it is accessing. The address of the PCA9551 is
shown in Figure 4. To conserve power, no internal pull-up resistors
are incorporated on the hardware selectable address pins and they
must be pulled HIGH or LOW.
1
1
0
0
A2
A1
A0
SLAVE ADDRESS
su01420
FIXED
HARDWARE SELECTABLE
R/W
Figure 4. Slave address
The last bit of the address byte defines the operation to be
performed. When set to logic 1 a read is selected while a logic 0
selects a write operation.
CONTROL REGISTER
Following the successful acknowledgement of the slave address,
the bus master will send a byte to the PCA9551 which will be stored
in the Control Register.
0
0
AI
B2
B1 B0
0
SW01034
0
AUTO-INCREMENT FLAG
REGISTER ADDRESS
RESET STATE: 00h
Figure 5. Control register
The lowest 3 bits are used as a pointer to determine which register
will be accessed.
If the auto-increment flag is set, the three low order bits of the
Control Register are automatically incremented after a read or write.
This allows the user to program the registers sequentially. The
contents of these bits will rollover to ‘000’ after the last register is
accessed.
When auto-increment flag is set (AI = 1) and a read sequence is
initiated, the sequence must start by reading a register different from
‘0’ (B2 B1 B0
0 0 0)
Only the 3 least significant bits are affected by the AI flag.
Unused bits must be programmed with zeroes.
CONTROL
REGISTER DEFINITION
B2
B1
B0
REGISTER
NAME
TYPE
REGISTER
FUNCTION
INPUT
REGISTER
FREQUENCY
PRESCALER 0
PWM
REGISTER 0
FREQUENCY
PRESCALER 1
PWM
REGISTER 1
LED0–LED3
SELECTOR
LED4–LED7
SELECTOR
0
0
0
INPUT
READ
0
0
1
PSC0
READ/
WRITE
READ/
WRITE
READ/
WRITE
READ/
WRITE
READ/
WRITE
READ/
WRITE
0
1
0
PWM0
0
1
1
PSC1
1
0
0
PWM1
1
0
1
LS0
1
1
0
LS1
REGISTER DESCRIPTION
INPUT — INPUT REGISTER
LED
7
bit
7
default
X
The INPUT register reflects the state of the device pins. Writes to
this register will be acknowledged but will have no effect.
LED
6
6
X
LED
5
5
X
LED
4
4
X
LED
3
3
X
LED
2
2
X
LED
1
1
X
LED
0
0
X
NOTE:
The default value “X” is determined by the externally applied
logic level, normally ‘1’ when used for directly driving LED with
pull-up to V
DD
.
PSC0 — FREQUENCY PRESCALER 0
1
bit
7
6
5
default
1
1
1
PSC0 is used to program the period of the PWM output.
4
1
3
1
2
1
1
1
0
1
The period of BLINK0
NOTE:
1. Prescaler calculation is different between the PCA9551 and
other PCA955x LED Blinkers. A divider ratio of 38 instead of 44
is used. This different divider ratio causes the blinking frequency
to be 13% (1 – 38/44) lower when the same 8-bit word is used.
The programmed value of the FREQUENCY PRESCALER must
be adjusted to compensate for this difference in applications
where the PCA9551 is used in conjunction with other PCA955x
LED Blinkers and the observed blinking frequencies need to be
the same.
PWM0 — PWM REGISTER 0
bit
7
6
5
default
1
0
0
The PWM0 register determines the duty cycle of BLINK0. The
outputs are HIGH (LED off) when the count is less than the value in
PWM0 and HIGH when it is greater. If PWM0 is programmed with
00h, then the PWM0 output is always LOW.
The duty cycle of BLINK0 is: 256 256
(PSC0
1)
38
4
0
3
0
2
0
1
0
0
0
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| PCA9551BS | 制造商:PHILIPS 制造商全稱:NXP Semiconductors 功能描述:8-bit I2C-bus LED driver with programmable blink rates |
| PCA9551BS,118 | 功能描述:LED照明驅(qū)動器 8-BIT I2C FM OD LED RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| PCA9551BS118 | 制造商:Rochester Electronics LLC 功能描述: 制造商:NXP 功能描述: 制造商:NXP Semiconductors 功能描述: |
| PCA9551BSHP | 功能描述:LED照明驅(qū)動器 RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
| PCA9551BS-T | 功能描述:LED照明驅(qū)動器 8-BIT I2C FM OD LED BLK RST RoHS:否 制造商:STMicroelectronics 輸入電壓:11.5 V to 23 V 工作頻率: 最大電源電流:1.7 mA 輸出電流: 最大工作溫度: 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SO-16N |
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