PCA9633_5 © NXP B.V. 2008. All rights reserved.
Product data sheet Rev. 05 — 25 July 2008 10 of 43
NXP Semiconductors
PCA9633
4-bit Fm+ I
2
C-bus LED driver
7.2 Control register
Following the successful acknowledgement of the slave address, LED All Call address or
LED Sub Call address, the bus master will send a byte to the PCA9633, which will be
stored in the Control register.
The lowest 4 bits are used as a pointer to determine which register will be accessed
(D[3:0]). The highest 3 bits are used as Auto-Increment flag and Auto-Increment options
(AI[2:0]). Bit 4 is unused and must be programmed with zero (0) for proper device
operation.
When the Auto-Increment flag is set (AI2 = 1), the four low order bits of the Control
register are automatically incremented after a read or write. This allows the user to
program the registers sequentially. Four different types of Auto-Increment are possible,
depending on AI1 and AI0 values.
Remark: Other combinations not shown in Table 6 (AI[2:0] = 001, 010, and 011) are
reserved and must not be used for proper device operation.
AI[2:0] = 000 is used when the same register must be accessed several times during a
single I
2
C-bus communication, for example, changes the brightness of a single LED. Data
is overwritten each time the register is accessed during a write operation.
AI[2:0] = 100 is used when all the registers must be sequentially accessed, for example,
power-up programming.
AI[2:0] = 101 is used when the four LED drivers must be individually programmed with
different values during the same I
2
C-bus communication, for example, changing color
setting to another color setting.
reset state = 80h
Remark: The Control register does not apply to the Software Reset I
2
C-bus address.
Fig 10. Control register
Table 6. Auto-Increment options
AI2 AI1 AI0 Function
0 0 0 no Auto-Increment
1 0 0 Auto-Increment for all registers. D3, D2, D1, D0 roll over to ‘0000’ after
the last register (1100) is accessed.
1 0 1 Auto-Increment for individual brightness registers only. D3, D2, D1, D0
roll over to ‘0010’ after the last register (0101) is accessed.
1 1 0 Auto-Increment for global control registers only. D3, D2, D1, D0 roll over
to ‘0110’ after the last register (0111) is accessed.
1 1 1 Auto-Increment for individual and global control registers only. D3, D2,
D1, D0 roll over to ‘0010’ after the last register (0111) is accessed.
002aab296
AI2 AI1 AI0 0 D3 D2 D1 D0
Auto-Increment flag
register address
Auto-Increment options