PCA9531PW 데이터 시트보기 (PDF) - Philips Electronics
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PCA9531PW Datasheet PDF : 20 Pages
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Philips Semiconductors
8-bit I2C LED dimmer
Product data
PCA9531
DEVICE ADDRESSING
Following a START condition the bus master must output the
address of the slave it is accessing. The address of the PCA9531 is
shown in Figure 4. To conserve power, no internal pullup resistors
are incorporated on the hardware selectable address pins and they
must be pulled HIGH or LOW.
SLAVE ADDRESS
1 1 0 0 A2 A1 A0 R/W
FIXED
HARDWARE SELECTABLE
su01420
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 PCA9531 which will be stored
in the Control Register.
0 0 0 AI 0 B2 B1 B0
RESET STATE: 00h
REGISTER ADDRESS
AUTO-INCREMENT FLAG
SW01034
Figure 5. Control register
CONTROL REGISTER DEFINITION
B2
B1
B0
REGISTER
NAME
TYPE
000
INPUT
READ
001
010
011
100
101
110
PSC0
PWM0
PSC1
PWM1
LS0
LS1
READ/
WRITE
READ/
WRITE
READ/
WRITE
READ/
WRITE
READ/
WRITE
READ/
WRITE
REGISTER
FUNCTION
INPUT
REGISTER
FREQUENCY
PRESCALER 0
PWM
REGISTER 0
FREQUENCY
PRESCALER 1
PWM
REGISTER 1
LED0-LED3
SELECTOR
LED4-LED7
SELECTOR
REGISTER DESCRIPTION
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
the input register (B2 B1 B0 0 0 0 0).
Only the 3 least significant bits are affected by the AI flag.
Unused bits must be programmed with zeroes.
INPUT — INPUT REGISTER
bit
7
6
5
4
3
2
1
0
Default X X X X X X X X
The INPUT register reflects the state of the device pins. Writes to
this register will be acknowledged but will have no effect.
PSC0 — FREQUENCY PRESCALER 0
bit
7
6
5
4
3
2
1
0
default 0
0
0
0
0
0
0
0
PSC0 is used to program the period of the PWM output.
The
period
of
BLINK0
+
(PSC0 ) 1)
152
PWM0 — PWM REGISTER 0
bit
7
6
5
4
3
2
1
0
default 1
0
0
0
0
0
0
0
The PWM0 register determines the duty cycle of BLINK0. The
outputs are LOW (LED on) when the count is less than the value in
PWM0 and HIGH (LED off) when it is greater. If PWM0 is
programmed with 00h, then the PWM0 output is always HIGH (LED
off).
The duty cycle of BLINK0 is:
PWM0
256
PSC1 — FREQUENCY PRESCALER 1
bit
7
6
5
4
3
2
1
0
default 0
0
0
0
0
0
0
0
PSC1 is used to program the period of PWM output.
The
period
of
BLINK1
+
(PSC1 ) 1)
152
PWM1 — PWM REGISTER 1
bit
7
6
5
4
3
2
1
0
default 1
0
0
0
0
0
0
0
The PWM1 register determines the duty cycle of BLINK1. The
outputs are LOW (LED on) when the count is less than the value in
PWM1 and HIGH (LED off) when it is greater. If PWM1 is
programmed with 00h, then the PWM1 output is always HIGH (LED
off) .
The duty cycle of BLINK1 is:
PWM1
256
LS0 — LED0-3 SELECTOR
LED 3
LED 2
LED 1
LED 0
bit
7
6
5
4
3
2
1
0
default 0
0
0
0
0
0
0
0
LS1 — LED4-7 SELECTOR
LED 7
LED 6
LED 5
LED 4
bit
7
6
5
4
3
2
1
0
default 0
0
0
0
0
0
0
0
The LSx LED select registers determine the source of the LED data.
00 = Output is set Hi-Z (LED off - default)
01 = Output is set low (LED on)
10 = Output blinks at PWM0 rate
11 = Output blinks at PWM1 rate
2003 Nov 10
5
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