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Hi,
There are 4 Columns and 16 Rows of LED Matrix.
I have circuit with Philips microcontroller with Port0 and Port1 connected to ULN2003 to Rows of the LED Matrix. While Port 2.2 to Port 2.7 (6 pins) are connected to 74LS245 buffer. The output of this buffer (Pin 11, 12 and 13) are connected to STCP, SHCP and DS Pin of 74HC595 shift register which is connected further to columns of the LED Matrix.
I can choose one row at a time, ON it by keeping all other rows OFF, and then want to ON the entire column. Can someone help me with some sample code to communicate 74LS245 and 74HC595 shift register through the microcontroller?
Regards RS.
I can choose one row at a time, ON it by keeping all other rows OFF, and then want to ON the entire column. Can someone help me with some sample code to communicate 74LS245 and 74HC595 shift register through the microcontroller? no, pin numbers are meaningless when you do not state the package which pins go to (you supply the right names) direction and OE on the '245 or are they tied, if so to what? why do you use '245 for a unidirectional buffer
Erik
74LS245 input pins-
DIR is connected to +5V (High) A1 to A8 are connected to P2.2(A10) to P2.7(A15) of Microcontroller
74LS245 output pins- B8->STCP & OE of 74HC595
B7->SHCP of 74HC595
B6->DS of 74HC595
I know only this much that 74LS245 is used as buffer.
I need some help on coding for 74LS245 with microcontroller and 74HC595, overall, how to pass the 1,0 from controller to the LEDs column.
A1 to A8 are connected to P2.2(A10) to P2.7(A15) of Microcontroller
Hmmm, that's 8 pins on one side, and 6 on the other. Sure you know what you're talking about?
yes, because, Pin number 4/5 and 8/9 of 74LS245 are connected with each other respectively.
The system has 64 columns and 16 Rows. Each 8 columns is connected to one shift register 74HC595. This 74HC595 STCP, SHCP and DS pins are connected from buffer IC 74LS245 which is connected to microcontroller. I have the link which you shared. Thanks for sharing. But I want to know how I should activate the columns from microcontroller to buffer 74LS245 to 74HC595?
So why are you connecting 4 with 5 and 8 with 9?
Do you feel that the poor little LS245 don't have enough juice to feed the other side from a single pin? Next thing is that if the DIR pin is switched, you will get multiple outputs connected together which is not a good idea.
Why are you using a 245 if you don't want dual direction? There are one-direction variants that have all inputs on one side and all outputs on the other side. LS541 would be a more natural choice. And why LS? Why not the HC/HCT family?
I need some help on coding for 74LS245 with microcontroller and 74HC595, overall, how to pass the 1,0 from controller to the LEDs column. when you realize that the '245 is just a buffer, the the datasheet of the '595 will tell you all you need to know.
Thanks Per. Actually the present circuit is working perfectly with software developed by another engineer. I am not much aware of the hardware part. I have been asked to developed a new software for the same microcontroller from scratch for the same circuit. So I am not able to reply the questions that you asked. I am looking for some help to start with this LS245 and HC595. Better I will scan and upload the circuit diagram here.