Technical Support

Technical Support

8051 Series issues

What kinds of universal writers can support Megawin 8051 IC ?

Universal Writer Support Web-site List:Please refer to Writer-maker web-site to check programmer type supported Megawin 8051 MCU in detail.




What is Frame Error Detection?

Frame Error Detection:

UART will begin with a “Low Bit” before transmitting the data (8 bits) and then end up with a “High bit”.

The wavy curve as below:




When Frame Error Bit (FE) is enabled by setting the SMOD0 (PCON.6) as 1, the receiver will detect an invalid stop bit, If the stop bit doesn’t indicate High, the EF will be set to 1. By the way, the EF will be kept as 1 unless it is reset as 0 by software.

What is 3-Level protection ?

Lock, Scramble, MOVC Disable.

Lock: When LOCK is enabled, MCU will be locked, which means any writer can’t read information form the MCU,The only way which you can do is Whole Chip Erase.

Scramble: When SB is enabled, the data in MCU will be scrambled. Even though the writer can read data from MCU, the data will be indiscriminate.

MOVC disable: When MOVCL is enabled, user will get empty value by using MOVC to read code, enable MOVCL can prevent your source code from being copied.

Why can*t I run my MCU while using 40 MHz Crystal?

t needs to parallel a 3.3K resistance to run the program when you use 32MHz crystal and the upward. Show as picture:

How do I reduce the EMI effect?

You may try the following steps to reduce the EMI effect:


1.       You can turn off ALE output if the circuit didn*t connect external memory, to turn off ALE output can setup AUXR to 0x01(Set A0 to 0).

2.       Use half a Fosc and Enable 6T.(You need use writer to set this Hardware Option)

3.       Enable OSCDN to reduce EMI output from crystal. (You need use writer to set this Hardware Option)

4.       Refer the table and picture as below to add a resistance.


X1 8MHz 12MHz 16MHz 20MHz 24MHz
C1,C2 47pF 47pF 47pF 47pF 47pF
R2,R3 OSCDN=1 33~680Ω 33~560Ω 33~430Ω 33~360Ω 33~300Ω
OSCDN=0 33~560Ω 33~470Ω 33~300Ω 33~220Ω 33~150Ω

How to connect external memory at MPC82G516?

To use external memory just need set P35ALE or P41ALE, if set ERAM to 1 means always use external memory or set ERAM to 0 means access external memory only when access over 1K bytes memory, by the way, the ALE pin is different with standard 8051, MPC82G516*s ALE pin is P3.5 or P4.1.

Do MPC82G516 will output 3V when input 5V?

Yes, V30 will output 3V, but v30 output current very weak, therefore we don*t suggest use this , and must notice also need connect a 0.1uF 每 0x33uF capacitance to GND.

Can I use 82G516 as a 64K flash for my application?

Yes, You can control 82G516 by SCL & SDA interface.

MPC82G516 have a little different with traditional 8051 MCU, who can I design my circuit?

If you didn*t connect external memory, MPC82G516 almost same as traditional 8051, but you most special note this: V30 is connect to IC core voltage, therefore if use in 5V system, this pin must tied a capacitance to ground, show as picture:

PS: This pin in traditional 8051 is EA, normally will tied to 5V, but in MPC82G516, V30 tied to 5V will make program error, or even make MCU broken.



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