PCA8546 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
Product data sheet Rev. 1 — 13 November 2013 7 of 63
NXP Semiconductors
PCA8546
4 x 44 automotive LCD driver
8. Functional description
The PCA8546 is a versatile peripheral device designed to interface any microcontroller to
a wide variety of LCDs. It can directly drive any multiplexed LCD containing four
backplanes and up to 44 segments.
8.1 Commands of PCA8546
The PCA8546 is controlled by 8 commands, which are defined in Table 5. Any other
combinations of operation code bits that are not mentioned in this document may lead to
undesired operation modes of PCA8546.
[1] Information about control byte and register selection see Section 9.1 on page 29.
8.1.1 Command: initialize
This command generates a chip-wide reset. It consists of two bytes which have to be sent
both to the device.
8.1.2 Command: OTP-refresh
During production of the device, each IC is calibrated to achieve the specified accuracy of
the frame frequency. This calibration is performed on EPROM cells called One Time
Programmable (OTP) cells. The device reads these cells every time the OTP-refresh
command is sent. The OTP-refresh command has to be sent after a reset has been made
and before the display is enabled.
Table 5. Commands of PCA8546
Command name Register
selection
RS[1:0]
[1]
Bits Reference
7 6 5 4 3 2 1 0
initialize Section 8.1.1
initialize-MSB 0000010110
initialize-LSB 0000000011
OTP-refresh 0011110000Section 8.1.2
mode-settings 000101BPSINVPDESection 8.1.3
oscillator-control 0 0 00011EFRCOEOSCSection 8.1.4
set-bias-mode 00000001B[1:0] Section 8.1.5
frame-frequency 00001FD[4:0] Section 8.1.6
load-data-pointer 0 0 1 0 DP[5:0] Section 8.1.7
write-RAM-data 0 1 D[7:0] Section 8.1.8
Table 6. Initialize - initialize command bit description
Bit Symbol Value Description
Initialize-MSB
7 to 0 - 00010110 fixed value
Initialize-LSB
7 to 0 - 00000011 fixed value
