8051 Development Board Help

Thread Starter

ClimateController

Joined Dec 23, 2012
19
I have been asked to design an 8051 development board for my class. They will be using it to make projects etc. Please have a look at the schematic attached below and tell me if there is anything missing.

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Features:
. 4 parallel I/O ports.
. 1 serial I/O port.
. A 5V power supply + an LED that is being used as an indicator.
. A manual reset circuit.
. 11 MHz crystal.

I would also like to know if the serial port and parallel ports are implemented correctly. I have a feeling the microcontroller will have trouble switching between the two modes of communication (serial and parallel) the way I have the ports set up here. Am I right?
 
Last edited:

pwdixon

Joined Oct 11, 2012
488
I believe RST is a low level not a high.
How are you going to program the device?
The voltage regulator is probably going to get quite warm.
 

pwdixon

Joined Oct 11, 2012
488
I will be using Hyper Terminal (comes with Windows XP) and the COM port on my computer. As far as I know, the RST is active high on the 8051.
I haven't used these devices but I wouldn't expect a simple serial link to be able to reprogram the device unless you have previously programmed in a bootloader somehow.

I have a datasheet for a Silicon Labs C8051F000/1/2/5/6/7 and that says RST is active low.
 

Thread Starter

ClimateController

Joined Dec 23, 2012
19
Thanks. I will look into it. Could I use C++ to read the COM port and use the data appropriately instead of using Hyper Terminal? I will be using another board in conjunction with this one. It will simply convert parallel sensor data into serial data. How do I set the baud rate of this board or is it something the USART takes care of? I know we can configure the baudrate through software on the microcontroller but this other board does not have one.
 

joeyd999

Joined Jun 6, 2011
4,269
...I wouldn't expect a simple serial link to be able to reprogram the device unless you have previously programmed in a bootloader somehow.
Does an 8051 even support self-programming? Last time I used one was back in 1988...perhaps things have changed since then?
 

absf

Joined Dec 29, 2010
1,942
Are you using THE "8051" from Intel or a variant of 8051 family chips?

The 8051/8052 has ROM inside but they are supposed to be programmed by the suppliers. The 8751 was the EPROM version of the 8051 that has a quartz window where you can erase the eprom for a finite number of times. I has used the 8031 which is a ROMledd version of the 8051.

The 89C51 are the flash version but you need an external programmer to program it. The 89S51 has in-circuit programming ICSP capability and can be programmed with only a few wires with the chip in the target PCB.

Allen
 

ScottWang

Joined Aug 23, 2012
6,832
Your circuit only can execution the program but it can't be programmed, it needs to programming the 89S51 on the other programming tool and put into this development board.

You can buy a 8051 programmer or make one by yourself as this one through printer port, I also built this and working fine.
 

ScottWang

Joined Aug 23, 2012
6,832
I haven't used these devices but I wouldn't expect a simple serial link to be able to reprogram the device unless you have previously programmed in a bootloader somehow.

I have a datasheet for a Silicon Labs C8051F000/1/2/5/6/7 and that says RST is active low.
The reset of C8051F000 is actived by low -- see page 21.
The reset of AT89S51 is actived by high -- see page 5.
 
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