Lcd frame frequency, Table 31. lcd frame frequencies (hz), Lcd display memory – Maxim Integrated MAXQ Family Users Guide: MAXQ2000 Supplement User Manual
Page 75: Maxq family user’s guide: maxq2000 supplement
LCD Frame Frequency
The LCD controller clock frequency (f
LCD
) can be sourced from either the 32kHz clock or the high-frequency clock divided by 128 as
specified by the LCCS bit. If Stop mode is entered and the 32kHz clock is being used, LCD display operation continues (if OPM = 1).
If Stop mode is entered and the high-frequency clock divided by 128 is being used, the LCD controller is suspended automatically
until Stop mode is exited and the high-frequency clock completes its warmup period.
The bits FRM[3:0] control the generation of the LCD frame frequency from the selected LCD clock source (32kHz or HFClk / 128). The
selected frame frequency (f
FRAME
) is defined as follows.
f
FRAME
= f
LCD
/ [((FRM[3:0]) + 1) x 96] for 1/3 duty
f
FRAME
= f
LCD
/ [((FRM[3:0]) + 1) x 64] for static, 1/2, and 1/4 duty
The resulting frame frequency should be between 30Hz and 1000Hz. Example frequencies that can be generated from typical clock
frequencies are shown in Table 31.
LCD Display Memory
The registers LCD0 to LCD16 provide 17 bytes of display memory. Depending on the duty cycle and package type, not all display
memory can be used by the LCD controller. Any display memory that is unused by the LCD controller can be used for application pur-
poses if desired. Tables 32 to 39 show the display memory mapping for different duty cycle and package configurations.
MAXQ Family User’s Guide:
MAXQ2000 Supplement
f
LCD
= 32,768Hz
f
LCD
= 7812.5Hz
(1MHz / 128)
f
LCD
= 38,400Hz
(4.9152MHz / 128)
f
LCD
= 62,500Hz
(8MHz / 128)
FRM[3:0]
1, 1/2, 1/4
1/3
1, 1/2, 1/4
1/3
1, 1/2, 1/4
1/3
1, 1/2, 1/4
1/3
0
512
341
122
81
600
400
977
651
1
256
171
61
41
300
200
488
326
2
171
114
41
27
200
133
326
217
3
128
85
31
20
150
100
244
163
4
102
68
24
16
120
80
195
130
5
85
57
20
14
100
67
163
109
6
73
49
17
12
86
57
140
93
7
64
43
15
10
75
50
122
81
8
57
38
14
9
67
44
109
72
9
51
34
12
8
60
40
98
65
10
47
31
11
7
55
36
89
59
11
43
28
10
7
50
33
81
54
12
39
26
9
6
46
31
75
50
13
37
24
9
6
43
29
70
47
14
34
23
8
5
40
27
65
43
15
32
21
8
5
38
25
61
41
Table 31. LCD Frame Frequencies (Hz)
Maxim Integrated
75