Radio7751-WalkMan

Multi-band radio based on NXP SAF7751, TEF6686, TEF6638.
The V1 version and the V2 version are not universal, please pay attention to distinguish them!
If you have any questions, please leave a message to communicate ~
 
The V1 version of the SAF7751 radio board module and control board information is as follows:
Receiving frequency bands
FM, FL, MW, LW, SW
 
System Introduction

RF reception: NXP SAF7751 radio supports long wave, medium wave, short wave, and FM band reception.
Power supply: TYPE-C fast charging input, built-in charging power management, lithium battery can be installed and carried with you.
Audio: Headphone amplifier;

 
more

backlight brightness can be adjusted and turned off, and backlight time is adjustable.
The threshold and speed can be set for automatic station search, and stations can be saved manually.
Power-off memory settings and saved radio

 
control components:
For details, see the attached file: Button Control Instructions.
 
Installation method:
Please refer to the attached installation method instructions for details of the illustrated version.
1. Insert the M2*7 bolts into the bottom shell and fix it with the 20mm high copper column nut.
2. Install the ipex to sma female adapter cable in the inner hole, and install the cable between the control board and the system board. The spacing between the cables 2.54mm;
3. When installing a polymer lithium battery, you can select a lithium battery of appropriate size and thickness according to the distance between the boards.
4. Put in the control board, pay attention to aligning the copper post holes, and install the key cap. The key cap specification is A101, and the inner diameter of the cap is 3.4mm.
5. Use a 5mm high M2 copper post with threads to fix the control board and the lower 20mm high M2 copper post. column.
6. Install the panel on the radio and fix the four corners with M2*7 bolts and the 5mm-high M2 copper pillars on the lower layer.
7. Install the knob bolts to fix the knob and the panel;
8. Install the aluminum alloy knob cap (13*13 plum blossom shape) and antenna, turn on the phone and plug in the headphones to listen.
 
The open source address of the control board firmware source code:
https://github.com/rayc345/WTCRC775X/tree/master
The attachment provides downloading of
 
the data in the M25P16 memory chip of the system board. The data in the memory chip of the system board can be flashed with the software in the attachment. The CH341A programmer for flashing the device is as shown in
 
the radio housing
3D. The printed shell has been uploaded as an attachment. M2 copper posts and bolts are used to connect the shell. Shell
size: 106x68x35mm, using 3D printing. The saf7751 chip heats up very much and the panel has many heat dissipation slits.
V3.1 version control board:
Update instructions:
1. When using battery power supply, the 5V LCD1602 writing is blurred because the voltage is not boosted. Now, the 3.3V LCD1602 is used instead, and the schematic diagram and PCB are updated at the same time. (20230329)
2. Modify the mid-circuit packaging and differential pair wiring issues. (20230427)
3. Modify an error in the system board schematic diagram, and the PCB is updated simultaneously. (20230610)
************************************************* *************************************************** **********************
4. The V2 version general control board MCU is replaced with stm32L051c8, and the display screen is replaced with 12864. (20230531)
5. The V2 and V3.0 versions of the universal control board only support external speakers.
6. The V2 version does not yet have a shell file, and it will be added later depending on the situation.
7. The V2 version control board 6638 radio board has been verified and is being continuously optimized.
8. Adjust the positions of the V2 control panel display, infrared and electrolytic capacitors. (20230620)
9. Update the TEF6686 radio board to V3, ensure that the upper and lower boards are the same size, and lead out DAC_L and DAC_R at the same time. (20230628)
10. Update the power amplifier control circuit of the V2 control board. (20230630)
11. The V2 version and 7751 radio board and the V3 version 6686 radio board have been successfully verified. All PCBs currently open source have been successfully verified. (20230705)
12. The general control panel is updated to version V3.0, the rotary encoder type and button position are modified, and a dual-speaker amplifier is adopted. (20230710)
13. The general control panel has been updated to version V3.1, and a headphone holder has been added, which can connect to external power amplifiers and speakers. (20230714)
14. Update the power amplifier control circuit of V3.0 and V3.1 control boards. (20230729)
15. Delete the V2 and V3.0 control panels, leaving the V1 version control panel, V3.1 version control panel and each radio panel. (20230802)
16. The V1 version control panel is only applicable to the V1 version of the radio board, and the V3.1 version of the control panel is only applicable to the V2 and V3 version of the radio board. (20230802)
17. There will be no further updates!