Teclast X21, Service Manual

Page: 19 / 76

R1
100K
FLASH3V3
/WP
FLASH3V3
D_GND D_GND
D_GND
R2
100K
C1
104
C2
104
U1
TC58512FT
NC
1
NC
2
NC
3
NC
4
NC
5
GND
6
RY/BY
7
RE
8
CE
9
NC
10
NC
11
Vcc
12
Vss
13
NC
14
NC
15
CLE
16
ALE
17
WE
18
WP
19
NC
20
NC
21
NC
22
NC
23
NC
24
NC
48
NC
47
NC
46
NC
45
I/O8
44
I/O7
43
I/O6
42
I/O5
41
NC
40
NC
39
NC
38
Vcc
37
Vss
36
NC
35
NC
34
NC
33
I/O4
32
I/O3
31
I/O2
30
I/O1
29
NC
28
NC
27
NC
26
NC
25
MPMC_AD7
MPMC_AD5
MPMC_AD6
MPMC_AD2
MPMC_AD0
MPMC_AD1
MPMC_AD3
MPMC_AD4
FLASH3V3
/RE
/CE
/WE
CLE
ALE
Figure 3.2.1.1 Flash circuit schematic diagram
2. Working principle: Flash Memory is the storage unit of the player and all Mp3 and waveform files
must be saved in FLASH. Flash module is composed of FLASH chip TC58512FT and peripheral circuit,
which fulfills the read, write and cancel working of internal files. In whic
ull-up resistor of /CE, R40 is pull-down resistor of /WP, Vcc is power supply pin of
FLASH, /CE is chip selection signal, VCC33 provides 3.3V voltage and FLASH begins to work. /RE, /WE
are effective read and effective write signal end respectively to control read and write function of FLASH.
I/O1 I/O8 is 8 data lines to fulfill the exchanges of FLASH and external data.
3.2.2 FM module circuit
1. FM module circuit schematic diagram is shown in the figure 3.2.2.1:
2. Working principle: FM module is composed of microwave digital tuning IC TEA5767HN produced
by Philips Company and the peripheral circuit, in which, L17, C54, C55 is the power supply filtering
circuit of FM module that provides IC with the pure voltage with typical value 2.8V. Cn1 is the socket
between FM module and main board.
h, 601 magnetic L15, 104
capacitor C45 and C46 compose FLASH power filtering circuit and provide FLASH with pure 3.3V
voltage. R38 is p
3.2.1 FLASH circuit principle
1. FLASH circuit schematic diagram is shown in the following figure 3.2.1.1:
Section Two Unit Circuit Principle
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