HD6473837H Datasheet, PDF (331/562 Pages) Renesas Technology Corp – Hardware Manual

13.2 Register Descriptions
13.2.1 LCD Port Control Register (LPCR)
The LCD port control register is an 8-bit read/write register, used for selecting the duty cycle and
the LCD driver and pin functions, etc. Upon reset, LPCR is initialized to H'00.
Bits 7 to 5—Duty and Common Function Select (DTS1, DTS0, CMX): Bits 7 to 6 select a
driver duty of static, 1/2, 1/3, or 1/4. Bit 5 determines whether the common pins not used at a
given duty are to be used as ports or, in order to increase the common driving capacity, as multiple
pins outputting the same waveform.
Bit 7: Bit 6: Bit 5:
DTS1 DTS0 CMX Duty
Common Driver*¹ Other Uses
0
0
0
Static COM₁ (initial value) COM₄, COM₃ and COM₂ usable as ports
1
COM₄ to COM₁
COM₄, COM₃ and COM₂ output the same
waveform as COM₁
0
1
0
1/2 duty COM₂ to COM₁
COM₄ and COM₃ usable as ports
1
COM₄ to COM₁
COM₄ outputs the same waveform as
COM₃, and COM₂ the same waveform as
COM₁
1
0
0
1/3 duty COM₃ to COM₁
COM₄ usable as port
1
COM₄ to COM₁
COM₄ outputs a non-select waveform*²
1
1
0
1/4 duty COM₄ to COM₁
—
1
Notes: 1. Pins COM₄ to COM₁ become ports when bit SGX = 0 and bits SGS3 to SGS0 = 0000.
Otherwise the common drivers are as indicated in the table above.
2. A non-select waveform is always output at pin COM₄, which therefore should not be
used.
Bit 4—Expansion Signal Select (SGX): Bit 4 selects whether pins SEG₄₀/CL₁, SEG₃₉/CL₂,
SEG₃₈/DO, and SEG₃₇/M are used as segment pins (SEG₄₀ to SEG₃₇) or as external segment
expansion pins (CL₁, CL₂, DO, M).
Bit 4: SGX
Description
0
Pins SEG₄₀ to SEG₃₇*
1
Pins CL₁, CL₂, DO, M
Note: * Selected as ports when bits SGS3 to SGS0 = 0000.
(initial value)
Bits 3 to 0—Segment Driver Select (SGS3 to SGS0): Bits 3 to 0 select the pins to be used as
segment drivers.
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