NXP Semiconductors
PCF8536
Universal LCD low multiplex driver with 6 channel PWM generator
Remark: If an external clock is used, then this clock signal must always be supplied to the
device when the display is on. Removing the clock may freeze the LCD in a DC state
which will damage the LCD material.
8.1.5.2 Timing and frame frequency
The timing of the PCF8536 organizes the internal data flow of the device. This includes
the transfer of display data from the display RAM to the display segment outputs. The
timing also generates the LCD frame frequency which it derives as an integer division of
the clock frequency (see Table 15). The frame frequency is a fixed division of the internal
clock or of the frequency applied to pin OSCCLK when an external clock is used.
Table 15. LCD frame frequencies
Frame frequency Typical external Nominal frame
frequency (Hz) frequency (Hz)
ffrLCD
=
-f-c---l-k----e---x--t--
48
9 600
200
ffrLCD = f--c-4--l-8k----e---xq--t-- 230000
200
EFR bit
0
1
Value of q[1]
-
24
[1] Other values of the frame frequency prescaler see Table 21.
When the internal clock is used, or an external clock with EFR = 1, the LCD frame
frequency can be programmed by software in steps of approximately 10 Hz in the range of
60 Hz to 300 Hz (see Table 21). Furthermore the internal oscillator is factory calibrated,
see Table 44 on page 59.
8.1.6 Command: GPO-output-config
The behavior of the combined LCD and GPO outputs S5/GP5 to S0/GP0 is configured
with the bits described in Table 16.
Table 16. GPO-output-config - output mode config command for S5/GP5 to S0/GP0
Bit
Symbol
Value
Description
GPM0 and GPM1
7 to 4 -
1100
fixed value
3 to 2 GPM1[1:0]
see Table 17 output mode for S1/GP1
1 to 0 GPM0[1:0]
see Table 17 output mode for S0/GP0
GPM2 and GPM3
7 to 4 -
1101
fixed value
3 to 2 GPM3[1:0]
see Table 17 output mode for S3/GP3
1 to 0 GPM2[1:0]
see Table 17 output mode for S2/GP2
GPM4 and GPM5
7 to 4 -
1110
fixed value
3 to 2 GPM5[1:0]
see Table 17 output mode for S5/GP5
1 to 0 GPM4[1:0]
see Table 17 output mode for S4/GP4
Each output can be individually configured to be either an LCD segment output, a PWM
output or a static general-purpose output (GPO), see Table 17.
Remark: Even if using GPO only, VLCD must still be applied to the device.
PCF8536
Product data sheet
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 6 October 2011
© NXP B.V. 2011. All rights reserved.
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